Proceedings of the Sixty-first Annual Meeting of the Northeastern Weed Science Society

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Proceedings of the Sixty-first Annual Meeting of the Northeastern Weed Science Society

Hilary A. Sandler, Editor University of Massachusetts-Amherst Cranberry Station East Wareham

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SUSTAINING MEMBERS Platinum Level

Gold Level

Silver Level AMVAC BAAR Scientific LLC Gowan Company K-I Chemical USA Olympic Horticultural Products PBI Gordon Bronze Level Marbicon, Inc. Reality Research USGA Green Section-Mid Atlantic Region Valent USA Corp Waldrum Specialties Weeds, Inc.

ACDS Research Crop Management Strategies J.C. Ehrlich Fore-Shore Weed Control IR-4 Project LABServices Inc.

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NORTHEASTERN WEED SCIENCE SOCIETY The Renaissance Harborplace Hotel Baltimore, MD EXECUTIVE COMMITTEE OFFICERS President

W. S. Curran The Pennsylvania State University Dept. Crop and Soil Sciences 423 ASI Building University Park, PA 16802

President-Elect

R.J. Keese Syngenta Crop Protection 985 Arrowhead Drive Carmel, IN 46033

Vice President

J.J. Baron IR-4 Project 500 College Rd. East, 201 West Princeton, NJ 08540

Secretary/Treasurer C.M. Becker BAAR Scientific LLC P.O. Box 34 Romulus, NY 14541 Past President

T.E. Dutt LABServices, Inc. 342 South Third Street Hamburg, PA 19526

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COMMITTEES Editor

H.A. Sandler UMass Cranberry Station P.O. Box 569 East Wareham, MA 02538

Legislative

D.L. Kunkel IR-4 Headquarters, Rutgers Univ. 500 College Road East, Suite 201W Princeton, NJ 08540

Public Relations

D.D. Lingenfelter The Pennsylvania State Univ. Dept Crop and Soil Sciences 116 ASI Building University Park, PA 16802

Research & Education Coordinator

K.M. Kalmowitz BASF Corporation 26 Davis Drive Research Triangle Park, NC 27709

Sustaining Membership

D. Spak Bayer Environmental Science 113 Willow Ridge New Holland, PA 17557

CAST Representative

R.D. Sweet Cornell University Dept. of Horticulture Ithaca, NY 14853

Graduate Student Rep.

J.N. Barney Cornell University Dept. of Horticulture Ithaca, NY 14853

WSSA Representative

A. DiTommaso Cornell University Dept. of Crop and Soil Sciences 903 Bradfield Hall Ithaca, NY 14853

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SECTION CHAIRS Agronomy

Chair: J. Jemison Chair-elect: G. Armel

Conservation, Forestry and Industrial

Chair: J. Johnson Chair-elect: N. Cain

Ornamentals

Chair: J. Atland Chair-elect: M. Marshall

Research Posters

Chair: B. Coffman Chair-elect: C. Palmer

Turfgrass and Plant Growth Regulators

Chair: L. Norton Chair-elect: M. Agnew

Vegetables and Fruit

Chair: D. Johnson Chair-elect: R. Lins

Weed Biology and Ecology

Chair: P. Bhowmik Chair-elect: M. VanGessel

Ornamental Workshop

Moderator: J. Atland

Turfgrass Symposium

Moderator: L. Norton

Horseweed Management Symposium

Moderator: M. VanGessel

Invasive Plant Symposium

Moderator: A. Gover

Organization Meeting for Invasives

Moderator: R. Beard

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RESEARCH POSTERS BIOLOGICAL CONTROL OF CANADA THISTLE IN PASTURES AND PARKS: A CALL FOR COLLABORATORS ON SIMPLE FIELD TESTS. D.K. Berner and P.A. Backman. 1 INTEGRATING WEED CONTROL STRATEGIES IN STRAWBERRIES DURING THE ESTABLISHMENT YEAR. R.R. Bellinder and C.A. Benedict......................................... 2 CONTROLLING 40 YEAR OLD KUDZU SITES IN PENNSYLVANIA. M. Bravo ........... 3 GIANT HOGWEED ERADICATION IN PENNSYLVANIA AND SURROUNDING STATES. M.A. Bravo...................................................................................................... 4 DOES POLYEMBRYONY CONFER GREATER COMPETITIVE ABILITY IN THE NONNATIVE INVASIVE VINE, PALE SWALLOW-WORT? M.L. Blanchard, A. DiTommaso, K.M. Averill, C.L. Mohler, and J.N. Barney ...................................................................... 5 EFFECTS OF EMERGENCE PERIODICITY ON GROWTH AND FECUNDITY OF HORSEWEED. J.T. Dauer, B.A. Scott and M.J. VanGessel, and D.A. Mortensen ........ 6 COMPARISON OF INTEGRATED WEED MANAGEMENT STRATEGIES IN CHRISTMAS TREE PLANTATIONS. M.W. Marshall, B.H. Zandstra, and R.J. Richardson ...................................................................................................................... 7 PRODUCER AND PRODUCTION IMPACTS OF BIOTECHNOLOGY-DERIVED HERBICIDE-RESISTANT CROPS PLANTED IN 2005. S. Sankula .............................. 8 A SIMPLE METHOD FOR CLEANING TUFTED WEED SEED. A. Senesac............... 10 INTERACTION OF BENSULIDE AND CARFENTRAZONE FOR MOSS CONTROL ON GOLF PUTTING GREENS. J.B. Willis, S.D. Askew, and J.S. McElroy........................ 11 EMERGENCE AND PERFORMANCE OF TWO SWALLOW-WORT SPECIES ON SOILS OF VARYING pH AND ORIGIN. L.C. Magidow, A. DiTommaso, L. Milbrath, and C.L. Mohler.................................................................................................................... 12 FLAZASULFURON: A POTENTIAL SOLUTION FOR SELECTIVE PERENNIAL RYEGRASS CONTROL IN CREEPING BENTGRASS. M.J. Goddard, S.D. Askew, J.B. Willis, and M.B. Grove................................................................................................... 13

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CARFENTRAZONE AND QUINCLORAC FOR WEED CONTROL DURING TURFGRASS ESTABLISHMENT. B.W. Compton, J.B. Willis, and S.D. Askew .......... 14 FENARIMOL TOLERANCE OF AN ANNUAL BLUEGRASS BIOTYPE. G.M. Henry, A.C. Hixson, and F.H. Yelverton ................................................................................... 15 2006 NEWSS SUMMER WEED CONTEST RESULTS. P.L. Rardon, G.R. Armel, D.R. Vincent, L.F. Houck, and M.C. McComrick.................................................................... 16 COMPARING SELECTED HERBICIDES TO METHYL BROMIDE FOR WEED CONTROL IN THREE HERBACEOUS PERENNIALS. D.A. Little, M.W. Marshall, R.J. Richardson, and B.H. Zandstra ..................................................................................... 17 INVASIVE AQUATIC WEEDS IN NORTH CAROLINA. R.J. Richardson, A.P. Gardner, S.T. Hoyle, and A.M. West ............................................................................................ 18 WEED PROPAGATION TECHNIQUES FOR USE IN DISCOVERING NEW HERBICIDES FOR TURF. M.S. Casini, L.F. Houck, G.R. Armel, and P.L. Rardon ..... 19 AMMONIUM PELARGONATE AS A BIOHERBICIDE FOR PEPPER ROW MIDDLES. B.A. Scott and M.J. VanGessel ..................................................................................... 20 BROCCOLI AND EDAMAME RESPONSES TO VINEGAR APPLICATION FOR WEED MANAGEMENT. C.B. Coffman, J. Radhakrishnan, and J.R. Teasdale ....................... 21 TRINEXAPAC-ETHYL INFLUENCES EFFICACY AND FOLIAR ABSORPTION OF BISPYRIBAC-SODIUM. P. McCullough and S. Hart .................................................... 22

AGRONOMY DOES BT CORN BENEFIT FARMERS IN MAINE: A ONE-YEAR, TWO LOCATION EVALUATION. J.M. Jemison, Jr., L. Titus and M. Titus ............................................... 23 POSTEMERGENCE ANNUAL GRASS CONTROL IN CORN WITH HPPD INHIBITORS. R.R. Hahn and P.J. Stachowski............................................................. 25 WEED CONTROL WITH TOPRAMEZONE PROGRAMS IN CORN. W.B. O’Neal, R.M. Porter, P.D. Vaculin and J.E. Orr .................................................................................. 26 THE IMPACT OF CULTIVATION TIMING AND INCREASED PLANT POPULATION DENSITY ON WEED CONTROL IN ORGANIC SOYBEANS. S.C. Reberg-Horton..... 27 vii

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ROTARY HOE EFFICACY IN CORN: INFLUENCE OF SOIL TYPE AND MOISTURE. M.G. Burton, C. Reberg-Horton, G.T. Place, and S.T. Hoyle ........................................ 28 EFFECTIVENESS OF A ROLLER/CRIMPER FOR CONTROL OF WINTER ANNUAL COVER CROPS. W. Curran, S. Mirsky, and M. Ryan.................................................. 29 ALFALFA/GRASS FORAGE MIXTURES USING GLYPHOSATE-RESISTANT ALFALFA. B.L. Dillehay, W.S. Curran, M. H. Hall, and D.A. Mortensen....................... 30 IMPROVING ELECTRONIC MANUSCRIPT REVIEW: NEW TECHNOLOGIES MAKE IT FASTER, EASIER, AND MORE BENEFICIAL. M.G. Burton and J.W. Wilcut.............. 31

ORNAMENTALS CONTROL OF NEW WEED SPECIES IN THE NURSERY INDUSTRY. J.F. Derr and J.C. Neal ....................................................................................................................... 32 EVALUATION OF GRANULAR HERBICIDES IN CONTAINER-GROWN WOODY ORNAMENTALS. S. Barolli and J. Ahrens................................................................... 33 SAFETY OF POSTEMERGENCE NUTSEDGE-CONTROL HERBICIDES ON ORNAMENTALS. J.C. Neal, J.F. Derr and A.F. Senesac ............................................ 35 TOLERANCES OF ORNAMENTAL SHRUBS TO HALOSULFURON, SULFENTRAZONE AND V-10142. T.L. Mervosh and J.F. Ahrens .............................. 36 UPDATE ON 2006 WEED SCIENCE RESEARCH IN THE IR-4 ORNAMENTAL HORTICULTURE PROGRAM. C.L. Palmer and J. Baron............................................ 37 2006 WEED MANAGEMENT TRIALS IN CHRISTMAS TREES. J. F. Ahrens............. 38 GROUND COVER SUPPRESSION IN NORTH CAROLINA FRASER FIR PRODUCTION. D. Hundley and J.C. Neal................................................................... 39 THE RESPONSE OF FIELD AND CONTAINER GROWN ORNAMENTALS TO SULFENTRAZONE AND FLUMIOXAZIN. M.W. Marshall and B.H. Zandstra.............. 40 THE EFFICACY AND CROP TOLERANCE OF PRE AND POSTEMERGENCE APPLICATIONS OF HALOSULFURON TO CHRISTMAS TREES. L.J. Kuhns and T.L. Harpster ........................................................................................................................ 41

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THE EFFICACY AND CROP TOLERANCE OF PREEMERGENCE APPLICATIONS OF SULFOMETURON PLUS HEXAZINONE TO CHRISTMAS TREES. L.J. Kuhns and T.L. Harpster ................................................................................................................. 42 HERBICIDES AS ALTERNATIVES TO METHYL BROMIDE FOR WEED CONTROL IN CONIFER SEEDLING BEDS. D.A. Little, M.W. Marshall, R.J. Richardson, and B.H. Zandstra ........................................................................................................................ 45

TURFGRASS AND PLANT GROWTH REGULATORS EVALUATION OF PROLINE-LINKED PENTOSE PHOSPHATE PATHWAY IN CREEPING BENTGRASS. D. Sarkar, P. Bhowmik, Y. I. Kwon, and K. Shetty............ 46 GENERIC PLANT GROWTH REGULATORS AND HERBICIDES IN TURF: HOW DO THEY COMPARE? T.W. Gannon and F.H. Yelverton.................................................. 47 ANNUAL BLUEGRASS AND DOLLAR SPOT CONTROL AS INFLUENCED BY HERBICIDES AND PLANT GROWTH REGULATORS. S.J. McDonald, M.A. Fidanza, and J. Fanok ................................................................................................................. 48 AUTUMN PREEMERGENCE AND SPRING POSTEMERGENCE CONTROL OF MOUSEEAR CHICKWEED AND CRABGRASS IN TURF. P.H. Dernoeden and J. Fu 49 THREE-WAY HERBICIDE COMBINATION CONTAINING FLUROXYPYR FOR POSTEMERGENT BROADLEAF WEED CONTROL IN TURF. D.L. Loughner, J.M Breuninger and M.W. Melichar ...................................................................................... 51

WEED ECOLOGY AND BIOLOGY A PRELIMINARY STUDY OF THE NON-NATIVE VASCULAR FLORA OF THREE COASTAL DELAWARE STATE PARKS. R. Stalter, E. Lamont, G. Grigoryan, and N. Faqeer........................................................................................................................... 52 EFFECTS OF BUCKWHEAT RESIDUE ON EMERGENCE AND EARLY GROWTH OF EIGHT WEED SPECIES. V. Kumar, D. C. Brainard, and R. R. Bellinder..................... 56 EVALUATION OF VARIOUS TRICLOPYR, CARFENTRAZONE-ETHYL, AND GLYPHOSATE COMBINATIONS POST-APPLIED ON JAPANESE KNOTWEED, INCLUDING THE EXPERIMENTAL HERBICIDE F-4113. A.Z. Skibo and M. Isaacs ... 57

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HURRICANES, AGING FORESTS, AND OVERABUNDANT WHITE-TAILED DEER: FACILITATORS OF INCREASED EXOTIC PLANT INVASION. J.L. Snitzer, H.M. McNett, K.L.A. Caraher, J. Bailey, K.L. Kyde, and D.H Boucher................................... 59 ENHANCED TOLEREANCE TO WEED COMPETITION: EFFECTS OF CROP AND SOIL MANAGEMENT IN A LONG-TERM CROPPING SYSTEMS TRIAL. M.R. Ryan, D.A. Mortensen, S.B. Mirsky, D.O. Wilson, R.M. Seidel, and P.R. Hepperly................. 60 THE ECOLOGY AND SPREAD OF INVASIVE SWALLOW-WORT SPECIES ACROSS NY STATE: DO ALLELOPATHY AND GENOTYPE PLAY A ROLE? C.H. Douglass and L.A. Weston................................................................................................................... 61 EFFECTS OF PLANTING AND TERMINATION DATE ON COVER CROP BIOMASS AND SUBSEQUENT WEED SUPPRESSION USING ROLLER/CRIMPER TECHNOLOGY. S.B. Mirsky, W.S. Curran, and M.R. Ryan......................................... 62 EFFECTS OF FLOATING ROW COVER ON WEED EMERGENCE AND STALE SEED BED PERFORMANCE. D.C. Brainard, R.R. Bellinder and V. Kumar........................... 63 A UNIFYING FRAMEWORK FOR SPECIES INTRODUCTIONS: THE STATE FACTOR MODEL. J.N. Barney and T.H. Whitlow........................................................................ 64 GERMINATION PATTERNS OF SWAMP DODDER SEEDS PLANTED NEAR A COMMERCIAL CRANBERRY FARM. H.A. Sandler and K. Ghantous ........................ 65 BIOLOGY OF MULTIFLORA ROSE: AN INVASIVE SPECIES. P. Bhowmik, D. Sarkar, and N. Tharayil .............................................................................................................. 66 AN OUNCE OF PREVENTION. M.J. VanGessel, D. Doohan, P.J. Christoffoleti, S.J.P. de Carvalho, and M. Nicolai .......................................................................................... 68

CONSERVATION, FORESTRY AND INDUSTRIAL RESPONSE OF PALE SWALLOW-WORT TO TRICLOPYR APPLICATION AND CLIPPING. K.M. Averill, A. DiTommaso, and S.H. Morris ............................................ 69 HERBICIDE COMPARISON IN WET BLADE APPLICATIONS FOR SWEET GUM, TULIP POPLAR, AND RED MAPLE CONTROL. A.R. Post and J.C. Neal, and C.A. Judge ............................................................................................................................ 70

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EVALUATION OF HERBICIDES FOR CONTROL OF MORROW’S HONEYSUCKLE USING FOLIAR TREATMENTS. J.M. Johnson, A.E. Gover, and L.J. Kuhns .............. 71 EFFICACY OF GLYPHOSATE, IMAZAPYR AND TRICLOPYR FOR PHRAGMITES MANAGEMENT IN A CONNECTICUT MARSH. T. L. Mervosh and D. P. Roach........ 73 EVALUATION OF HERBICIDES FOR CONTROL OF JAPANESE KNOTWEED. J.M. Johnson, A.E. Gover, and L.J. Kuhns ........................................................................... 74 EVALUATION OF HERBICIDES FOR CONTROL OF AUTUMN OLIVE USING FOLIAR TREATMENTS. J.M. Johnson, A.E. Gover, and L.J. Kuhns ........................................ 76 HOT WATER SYSTEMS FOR VEGETATION MANAGEMENT. R.G. Prostak and A.V. Barker............................................................................................................................ 78 RAPID RESPONSE TO THE INVASIVE VINE, BUSHKILLER, IN NORTH CAROLINA. R.J. Richardson, A.M. West, and A.P. Gardner ............................................................ 79

TURFGRASS AND PLANT GROWTH REGULATORS SEEDHEAD SUPPRESSION OF ANNUAL BLUEGRASS ON A PUTTING GREEN IN 2006. M.B. Naedel and J.A. Borger.............................................................................. 80 THE EFFECTS OF FERTILIZER ON THE TOLERANCE OF KENTUCKY BLUEGRASS TO BISPYRIBAC-SODIUM HERBICIDE. R.R. Shortell, S.A. Bonos, and S.E. Hart .... 81 ROUGHSTALK BLUEGRASS CONTROL WITH BISPYRIBAC-SODIUM AND SULFOSULFURON. P. McCullough and S. Hart ......................................................... 82 CRITICAL WEED-FREE PERIOD FOR OVERSEEDED BERMUDAGRASS IN NORTHERN CLIMATES. B.W. Compton and S.D. Askew .......................................... 83 EFFECT OF DEW AND GRANULAR FORMULATION ON MESOTRIONE EFFICACY FOR LAWN WEED CONTROL. M.J. Goddard, S.D. Askew, J.B. Willis, R.J Keese, and J.R. James .................................................................................................................... 84 ABSORPTION, TRANSLOCATION, AND METABOLISM OF FORAMSULFURON IN DALLISGRASS. G.M. Henry, J.D. Burton, and F.H. Yelverton .................................... 85

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USE OF TRICLOPYR TO REDUCE ANTICHROMATIC EFFECTS OF MESOTRIONE IN TURFGRASS. J.B. Willis and S. D. Askew.............................................................. 86 METHODS TO ASSESS ENVIRONMENTAL INFLUENCE ON TURFGRASS RESPONSE TO MESOTRIONE. S.D. Askew, M.J. Goddard and J.B. Willis............... 87 YELLOW NUTSEDGE CONTROL WITH SULFENTRAZONE, SULFOSULFURON AND MESOTRIONE. P.H. Dernoeden, J. Fu, and S.J. McDonald ....................................... 88 PRELIMINARY STUDY AT FOUR LOCATIONS ON USING GROWING DEGREEDAYS TO APPLY A PREMERGENCE HERBICIDE. M.A. Fidanza, J.A. Borger and M.B. Naedel, C.A. Bigelow, and P.C. Bhowmik............................................................. 89 PRE AND POST EMERGENT ANNUAL BLUEGRASS CONTROL. J.A. Borger, M.B. Naedel, M.D. Soika and T.L. Watschke......................................................................... 90 APPLICATOR EXPOSURE AND DRIFT OF LAWN CHEMICALS WITH A WET BLADE MOWER AND THREE FOLIAR SPRAY METHODS. S.D. Askew ............................... 91

VEGETABLES AND FRUIT PUMPKIN RESPONSE TO HALOSUFSULFURON, FOMESAFEN, AND TERBACIL. R.B. Batts, A.W. MacRae, and J.B. Beam..................................................................... 92 ASSESSMENT OF THE COMBINED EFFECTS OF MESOTRIONE AND HEXAZINONE ON WEEDS IN WILD MAINE BLUEBERRIES. D.E. Yarborough and K.F.L. Guiseppe ............................................................................................................ 93 THE ADVANTAGES OF QUINCLORAC OR MESOTRIONE USE IN CRANBERRY BOG ESTABLISHMENT. B.A. Majek ........................................................................... 95 CHEMICAL CONTROL OF APPLE ROOT SUCKERS WITH COMMERCIAL APPLICATION EQUIPMENT. W.H. Palmer ................................................................. 96 CHEMICAL CONTROL IN ORCHARDS WITH COMMERCIAL APPLICATION EQUIPMENT. W.H. Palmer and D.I. Breth................................................................... 97 STRAWBERRY PLANTING YEAR WEED CONTROL: THE NEED FOR ADDITIONAL HERBICIDES. C.A. Benedict and R.R. Bellinder ......................................................... 98

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BEING HEARD BY THE IR-4 PROJECT. E. Lurvey .................................................... 99 WEED CONTROL IN NO-TILL PUMPKINS. D.H. Johnson and D.D. Lingenfelter..... 100 EVALUATING TRIKETONES IN SWEET CORN. R.R. Bellinder and C.A. Benedict . 101 NATURAL PRODUCT POTENTIAL FOR WEED CONTROL IN POTATO. G.J. Evans and R.R. Bellinder ....................................................................................................... 102 WEED CONTROL IN NO-TILL SWEET CORN. D.D. Lingenfelter and D.H. Johnson103 THE IR-4 PROJECT: UPDATE ON HERBICIDE REGISTRATION. M. Arsenovic, F.P. Salzman, D.L. Kunkel, and J.J. Baron......................................................................... 104

ORNAMENTAL WORKSHOP ORNAMENTAL WORKSHOP 2007. J. Altland .......................................................... 105

TURFGRASS SYMPOSIUM PEDIGREE OF A PESTICIDE. D.R. Spak and N.M. Hamon ..................................... 106 HOW GOLF COURSE SUPERINTENDENTS VIEW NEW HERBICIDE COMPOUNDS. S. Zontek..................................................................................................................... 107 SEEDHEAD SUPPRESSION OF ANNUAL BLUEGRASS. J.A. Borger and M.B. Naedel .................................................................................................................................... 108 BISPYRIBAC-SODIUM (VELOCITY) USE ON GOLF COURSES FOR ANNUAL BLUEGRASS AND ROUGHSTALK BLUEGRASS CONTROL. S.E. Hart and P.E. McCullough ................................................................................................................. 109 APPLICATIONS FOR SULFENTRAZONE USE ON GOLF TURFS. S.J. McDonald and P.H. Dernoeden .......................................................................................................... 110 SELECTIVE REMOVAL OF CREEPING BENTGRASS WITH MESOTRIONE. J.E. Kaminski...................................................................................................................... 111

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HORSEWEED MANAGEMENT SYMPOSIUM HORSEWEED: FROM OBSCURITY TO THE LIMELIGHT. M.J. VanGessel ............ 112 HOW THE SPATIAL SCALE OF DISPERSAL MODELING HAS INCREASED WITH GLYPHOSATE-RESISTANT HORSEWEED. J.T. Dauer, D.A. Mortensen, E.C. Luschei, M.J. VanGessel, and E.S. Shields ................................................................ 113 RECENT FINDINGS ON THE FIELD BEHAVIOR, GENETICS, AND MECHANISM OF GLYPHOSATE-RESISTANCE IN HORSEWEED. D.I. Gustafson, M.T. Faletti, G.R. Heck, R.D. Sammons, and M.B. Spaur ....................................................................... 114 HORSEWEED EMERGENCE, SURVIVAL, AND SEEDBANK DYNAMICS IN SOUTHEASTERN INDIANA AGROECOSYSTEMS. W.G. Johnson, V.M. Davis, and K.D. Gibson................................................................................................................. 115 HORSEWEED RESPONSE TO NO-TILL PRODUCTION SYSTEMS. M.J. VanGessel, B.A. Scott, Q.R. Johnson and S.E. White.................................................................... 116 DO ECOLOGICAL INSIGHTS INFORM CONYZA MANAGEMENT? D.A. Mortensen, J.T. Dauer, W.S. Curran and M.J. VanGessel............................................................. 117

INVASIVE PLANT SYPOSIUM: RIPARIAN FORST BUFFERS THE MASSACHUSETTS EXAMPLE: ONE STREAM BANK, MULTIPLE JURISDICTIONS. R.G. Prostak and D.J. Picking ....................................................... 118

SUPPLEMENT TO THE 60TH PROCEEDING ABSTRACTS FROM THE 60TH NEWSS MEETING THE EFFECTS OF CULTURAL PRACTICES ON WEED ESTABLISHMENT IN CONTAINERS. J. Altland ........................................................................................... 120 AMINOPYRALID: A NEW HERBICIDE FOR BROADLEAF WEED CONTROL IN PASTURE, ROADSIDE, AND NATURAL AREAS. P.L. Burch and E.S. Hagood ...... 121

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ABSTRACTS FROM THE 7TH CONFERENCE OF THE NORTHEAST AQUATIC PLANT MANAGEMENT SOCIETY EVALUATION OF REGISTERED AND EUP HERBICIDES FOR CONTROL OF VARIABLE MILFOIL. M.D. Netherland....................................................................... 123 EVALUATION OF AN HERBICIDE APPLICATION ON VEGETATED HABITAT AND THE STRUCTURE OF A FISH AND MACROINVERTEBRATE COMMUNITY IN MINNESOTA LAKES. J.G. Slade and E.D. Dibble..................................................... 124 USE OF THE AQUATIC HERBICIDE RENOVATE™ (TRICLOPYR) IN PHRAGMITES AUSTRALIS CONTROL PROGRAMS. D. Roach and S. Living ................................ 125 ALUMINUM TREATMENT FOR PHOSPHORUS AND ALGAE CONTROL: WHAT, WHY, WHERE AND WHEN. K.J. Wagner ................................................................. 126 INTEGRATED AQUATIC WEED MANAGEMENT IN TURFGRASS AREAS. J. Whetstone ................................................................................................................... 127 BIOLOGICAL CONTROL OF AQUATIC WEEDS 1959-2005. J.F. Shearer .............. 128 THE SUCCESSFUL CONTROL OF JAPANESE KNOTWEED IN A RIPARIAN SETTING. A. Gover, K. Budd, J.M. Lentz, and R.R. Johnson.................................... 129 THE 2002 FARM BILL AND ITS EFFECT ON INVASIVE PLANT MANAGEMENT IN NEW ENGLAND. A. Lipsky ........................................................................................ 130 THE IR-4 PROJECT: NEW OPPORTUNITY FOR AQUATIC HERBICIDE................. 131 LAND USE PRACTICE IMPACTS ON NORTHEAST AQUATIC PLANT MANAGEMENT. P.H. Lord and R.L. Johnson ........................................................... 132 WATER QUALITY AFFECTS DUE TO A CONTINUOUS LAKE WIDE MILFOIL CANOPY IN A SHALLOW CT LAKE. G.W. Knoecklein ............................................. 133 A NEW STANDARD FOR DEFINING AQUATIC PLANT COMMUNITY COMPOSITION IN NEW YORK. S.A. Kishbaugh, P.H. Lord, and R.L. Johnson ................................. 134

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MUSKRAT HOUSE ABUNDANCE, WATER LEVEL MANAGEMENT, AND CATTAIL CONTROL WITHIN UPPER ST. LAWRENCE RIVER TRIBUTARY WETLANDS. J. Toner, J. Farrell, and J. Mead ..................................................................................... 135 PORTRAIT OF THE HEALTH STATUS OF LAKES: C. Rivard-Sirois ........................ 136 BIOLOGICAL CONTROL OF EURASIAN WATERMILFOIL BY THE MOTH AND WEEVIL: FACT AND FICTION. R.L. Johnson, P.H. Lord, and J.M. Riggs................. 137 TEN YEARS OF VARIABLE WATER MILFOIL CONTROL IN BASHAN LAKE. WHAT HAVE WE LEARNED. G. Bugbee.............................................................................. 138 A UNIQUE COMBINATION OF AGENCIES AND COMPANIES WORKING TOWARDS SUCCESSFUL MANAGEMENT OF INVASIVE PLANTS. L. Lyman.......................... 139

REPORTS, AWARDS, MEMBERSHIP, HERBICIDE LISTS, AND INDICES PRESIDENTIAL ADDRESS, 60th ANNUAL MEETING ............................................... 140 MINUTES FOR THE 60TH ANNUAL BUSINESS MEETING...................................... 145 NEWSS EXECUTIVE COMMITTEE REPORTS ......................................................... 151 NEWSS FINANCIAL STATEMENT FOR 2005 ........................................................... 155 NEWSS PAST PRESIDENTS ..................................................................................... 172 AWARD OF MERIT ..................................................................................................... 173 DISTINGUISHED MEMBERS ..................................................................................... 175 OUTSTANDING RESEARCHER AWARD .................................................................. 176 OUTSTANDING EDUCATOR AWARD ....................................................................... 176 OUTSTANDING GRADUATE STUDENT PAPER CONTEST ..................................... 177 COLLEGIATE WEED CONTEST WINNERS............................................................... 180 RESEARCH POSTER AWARDS ................................................................................ 184 INNOVATOR OF THE YEAR....................................................................................... 188 OUTSTANDING APPLIED RESEARCH IN FOOD AND FEED CROPS ...................... 188 OUTSTANDING APPLIED RESEARCH IN TURF, ORNAMENTALS, ETC. ................ 188 OUTSTANDING PAPER AWARDS............................................................................. 189 NEWSS MEMBERSHIP DIRECTORY ........................................................................ 195

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HERBICIDE NAMES: COMMON, TRADE, AND CHEMICAL ..................................... 210 COMMON PRE-PACKAGED HERBICIDES ............................................................... 220 EXPERIMENTAL HERBICIDES.................................................................................. 223 PLANT GROWTH REGULATORS.............................................................................. 223 COMMON AND CHEMICAL NAMES OF HERBICIDE MODIFIERS........................... 224 AUTHOR INDEX ......................................................................................................... 225 MAIN SUBJECT INDEX .............................................................................................. 228

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BIOLOGICAL CONTROL OF CANADA THISTLE IN PASTURES AND PARKS: A CALL FOR COLLABORATORS ON SIMPLE FIELD TESTS. D.K. Berner, USDA, ARS, FDWSRU, Ft. Detrick, MD and P.A. Backman, Dept of Plant Pathology, The Pennsylvania State Univ., University Park. ABSTRACT Canada thistle (Cirsium arvense (L.) Scop.) is one of the most noxious invasive weeds in North America. It occurs on millions of acres of pastures, agricultural land, and natural areas. It is difficult to control because it has an extensive root system and reproduces by seeds and root buds, the latter of which are multiplied and distributed by plowing. It can be controlled by intensive herbicide applications, but in pastures and natural areas this is economically prohibitive. Biological control may affordable and effective. The obligate rust fungus, Puccinia punctiformis (F. Strauss) Rohl., is perhaps the first plant pathogen proposed as a biological control agent for Canada thistle or any other weed. In 1893 a NJ farmer noticed diseased thistle patches virtually disappeared after a few years; he proposed that the rust should be widely disseminated for weed control. Successful biological control of Canada thistle using P. punctiformis is hindered due largely to a heterogeneous distribution of teliospores in the soil leading to low incidence of systemically infected (SI) shoots. Homogeneous distribution of teliospores over extended periods of time may overcome this problem. In 2003-2005, we conducted experiments in two field sites naturally infested with Canada thistle and the rust. SI thistle shoots in each replicate in each field site were counted, and randomly selected plots were mowed while others remained unmowed. Our hypotheses were that a) mowing could remove apical dominance and result in emergence of more SI shoots within the current and subsequent growing seasons, and b) mowing could re-distribute teliospores from SI shoots and result in more homogeneous distribution and greater number of diseased shoots the following season. Mowing increased numbers of SI shoots within and between seasons compared to unmowed plots. Numbers of SI shoots in unmowed plots also increased, but not to the degree of the mowed plots. Results were consistent with a 1923 study, which indicated that in unplowed pastures, SI shoots increased exponentially. Predictions from both studies indicated that 100% disease incidence could be expected in mowed and unmowed plots within 2.7-5.2 yr of disease establishment. With greater initial disease (shoots), progression to 100% disease incidence might proceed more rapidly. We propose to field-test, in multiple pasture and natural area sites, the ability of the rust to reduce healthy thistle density. We would produce SI seedlings in our facilities and place them in Canada thistle patches. This should provide prolonged production of teliospores and more homogeneous distribution of inoculum. We seek collaborators to help establish test sites and monitor disease progression and healthy thistle density. Our procedures for establishing disease and monitoring field sites will be presented.

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INTEGRATING WEED CONTROL STRATEGIES IN STRAWBERRIES DURING THE ESTABLISHMENT YEAR. R.R. Bellinder and C.A. Benedict, Cornell Univ., Ithaca, NY. ABSTRACT Managing weeds during the establishment year is crucial to the long-term productivity of strawberries. Growers need to rely on a management system that can be maintained until the crop becomes established and competitive. Current practices that solely rely on herbicides, usually result in the need for large amounts of hand-labor and cultivation that dramatically increase operational costs. Recent research has shown that inter-seeding a cover crop or living mulch to suppress between-row weeds has some promise. In the spring of 2006, seven treatments were applied to plots having one row each of the varieties 'Earliglow' and ‘Jewel’. The treatments were: A.) Standard Broadcast Herbicide, B.) Standard Broadcast Herbicide + Fescue, C.) Banded Herbicide + Cultivation(Between+In-row), D.) Banded Herbicide + Fescue, E.) Fescue + In-row cultivation, F.) Between + In-row cultivation only, and G.) Hand-weeded Check. All applications were made using a CO2 sprayer that delivered 34 GPA. In-row cultivation was done with a Buddingh Finger Weeder (Buddingh Weeder Co., Dutton MI) and a torsion weeder (Bezzerides Brothers, Orosoi, CA). An s-tine cultivator was used between rows. Data collection included weed counts and dry weights and runner production and number throughout the growing season. Total weed numbers were lowest in treatment C followed by B, F, D, A, E, and G, respectively. The banded herbicide+cultivation treatment had both the lowest number of in- and between-row weeds. Total and in-row weed dry weights were lowest in broadcast+fescue. Whereas, between+in-row cultivation was lowest in between-row weights. The similarity of in-row weights was due to a few, large weeds surviving. In fescue treatments, a decrease in the number of runners per plant can be attributed to the management of the fescue. Cultivation did not have a detrimental impact on runner production.

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CONTROLLING 40 YEAR OLD KUDZU SITES IN PENNSYLVANIA. M. Bravo, The Pennsylvania State Univ., University Park. ABSTRACT Pennsylvania appears to be the first state in the U.S. to have received kudzu (Pueraria montana (Lour.) Merr.). In 1876 the Japanese pavilion of the Philadelphia Centennial Exposition displayed live kudzu. A herbarium specimen (Carnegie Museum) currently on loan to the PA Agriculture Museum in Harrisburg dates kudzu in West End Park, Pittsburgh to 1920. It is unknown if this is the same kudzu patch that was eradicated in West End Park by Pittsburgh Public Works employee Jim Foley in 2003. Current sites in PA are most often roadside banks, forest areas, quarries, slag mine deposits, homeowner property boundaries and rarely open space locations such as pipelines. Kudzu locations in PA have routinely been monitored since the early 1980’s. Since the advent of soybean rust, renewed interest in limiting the spread of kudzu began in PA. During Summer 2006, the Department sought to confirm the known locations of kudzu in the state. As of October at least 71 known sites of kudzu are documented. At least 48 of these sites were actively producing vegetation. Seed production has been documented at many sites in the state since the 1980’s and most of the untreated sites in 2006 were producing seed. Historical information and the physical data collected at each site suggests all current kudzu sites in PA are at least 30 years old and were purposely planted for soil stabilization or other recommended uses provided during the height of its promotion in the late 1930’s. The current distribution range of kudzu in PA seems limited to Zone 6. A pilot Kudzu Eradication Program began in 2000 with 5 locations treated. By the end of 2006, 18 more locations were enrolled. Herbicides used since 2000 include aminopyralid, clopyralid, metsulfuron and triclopyr. The goal of the program is to treat sites for 3 consecutive years to assist property owners in eradicating persisting sites of kudzu. Treatments at 6 sites in Lebanon County were used as a research plot to collect baseline data on clopyralid efficacy, rate and longevity. These sites were a combination of virgin sites, previously treated sites, roadside banks, forest areas and open space areas. Treatment applications included: high volume (HV) foliar, low volume (LV) broadcast and a 2% v/v cut stump application. Applications were monitored at 4, 7, 10, 11, 13 and 16 wk after treatment (WAT). In summary, all May-cut stump, HV foliar and LV broadcast treatments were still preventing vegetative re-growth at 16 WAT. However, “missed” vegetation was common at every site and untreated vegetation was discovered at every site through July. A single HV foliar application followed by LV broadcast spot treatments successfully prevented vegetative re-growth of all open space and roadside bank infestations. Cut stump applications were critical to 100% control in all forest areas due to mature vines throughout the sites. Alarmingly, a cohort (> 50) of kudzu seedlings emerged in late July in a construction road that was cut through one of the virgin forest area sites in 2005. This indicates that seeds are viable and movement of soil may allow naturalized populations of kudzu to become established in PA.

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GIANT HOGWEED ERADICATION IN PENNSYLVANIA AND SURROUNDING STATES. M.A. Bravo, Pennsylvania Department of Agriculture, Harrisburg. ABSTRACT Heracleum mantegazzianum introduction to Europe, from its native Caucasus Mountains, dates back to 1817. By the late 1840's reports of wild populations of giant hogweed were documented in the United Kingdom. Currently 21 European countries have reported wild populations of giant hogweed. In the United States an increase in reports of wild populations is also occurring. Giant hogweed was added to the federal noxious weed list in 1983. Giant Hogweed is in its element here in the temperate region of the Northeastern states. In the last decade, 16 states (WA, OR, MI, IA, IN, WI, OH, PA, NY, NH, ME, VT, MA, CT, NJ, MD) have confirmed finding giant hogweed. PA first discovered giant hogweed in 1985 in Erie County. A joint effort between PDA and USDA in 1998 established the Giant Hogweed Eradication Program. Currently, PA has less than 600 sites with viable hogweed populations in 12 counties. Federal support for the project has been strong and as a result of the PA efforts, many other States are actively searching for Giant Hogweed and conducting outreach programs. In the fall of 2005, the Program Review Committee for Giant Hogweed met in Pennsylvania and outlined the following goals for 2006. Goals for Pennsylvania and other States in the Region for 2006 were 1) eradicating persisting, but isolated populations in outlying counties 2) developing a standardized database to assist in evaluating the successful of the eradication programs 3) acquiring regional staffing and funding to implement control measures in adjoining states 4) emphasizing the risk of infestations becoming established in riparian areas and 5) encouraging local and regional research on the ecology an biology of giant hogweed to assist the eradication program in understanding the long term population dynamics of this invasive species. Like most invasive primers, giant hogweed’s reproductive potential is enormous. Plants reproduce by seed and perenniating crown and rootbuds and have a high regeneration ability to set seed if seed heads are removed prior to maturity. A single plant is capable of yielding more than 100,000 seeds, primarily by out-crossing. Rosettes of giant hogweed can persist for as long as 12 years before flowering and understanding the biology of giant hogweed is critical to implementing a successful eradication program.

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DOES POLYEMBRYONY CONFER GREATER COMPETITIVE ABILITY IN THE NONNATIVE INVASIVE VINE, PALE SWALLOW-WORT? M.L. Blanchard, A. DiTommaso, K.M. Averill, C.L. Mohler, and J.N. Barney, Cornell Univ., Ithaca, NY. ABSTRACT Pale swallow-wort (Vincetoxicum rossicum (Kleopow) Barbar) is a non-native invasive vine in the Asclepiadaceae that has colonized natural systems in many Northeastern States and several Canadian provinces. It is a twining herbaceous perennial vine that can spread vegetatively, but reproduces primarily by seeds, some of which exhibit polyembryony (i.e., a condition where a single seed can produce multiple seedlings). Polyembryony occurs in a significant percentage of pale swallow-wort seeds, and may allow the plant to more effectively colonize areas as well as outcompete other plants for resources. Little is known about how polyembryony in this invasive plant affects competitive outcomes. Thus, the effect of polyembryony in pale swallow-wort on intra- and inter-specific competition was evaluated in a greenhouse experiment using a modified replacement series design. Pale swallow-wort plants from three polyembryonic classes; singles, doubles, and triples (i.e., one, two, and three seedlings per seed, respectively) were grown with each other in all combinations and with the native species, Canada goldenrod (Solidago canadensis L.) and common milkweed (Asclepias syriaca L.). A total density of 2 plants per pot was used. The height and number of nodes (rosette width for goldenrod) were recorded for pale swallow-wort and milkweed plants every two weeks for 10 weeks, and then 4 weeks later at the end of the experiment. After this 14-wk period, all plants were harvested and above- and below-ground biomass determined. In general, pale swallow-wort plants consisting of one seedling (singles) had significantly lower total biomass when competing with pale swallow-wort plants having two or three seedlings and with goldenrod and milkweed than with other single-seedling swallow-wort plants. These reductions in growth of single-seedling plants were most evident for belowground biomass. There was no significant difference between goldenrod and milkweed in their negative effect on pale swallow-wort. These findings suggest that the production of more than one seedling via polyembryony in pale swallow-wort may be advantageous in competitive environments.

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EFFECTS OF EMERGENCE PERIODICITY ON GROWTH AND FECUNDITY OF HORSEWEED. J.T. Dauer, The Pennsylvania State Univ., University Park, B.A. Scott and M.J. VanGessel, Univ. of Delaware, Georgetown, and D.A. Mortensen, The Pennsylvania State Univ., University Park. ABSTRACT The dispersal ability of winter annual and summer annual biotypes of horseweed (Conyza canadensis) was assessed along a 400 km latitudinal gradient between Pennsylvania and Delaware. Dispersal ability was defined by time of seed set, plant height and fecundity. Earlier seed set can result in greater opportunities for fall establishment and taller plants increase seed release height and impact dispersal distance. Greater fecundity increases the opportunities for populations to sample diverse environments and establish satellite populations. Sites were located in central and southeastern Pennsylvania, and central and southern Delaware with trials initiated in fall 2005 and replicated in fall 2006. Plots were arranged in a randomized complete block with four replications of two fall and two spring cohorts. Early and late cohorts were determined by germination before or after October 1st (fall) and April 15th (spring). Ten plants were randomly selected in each replicate, marked, and revisited biweekly to record plant height and percent flowering. Following seed release, final plant height was measured and capitula per plant were counted to estimate seed production. The late fall cohort was eliminated due to lack of overwintering success in Pennsylvania populations and data were averaged within a plot. In 2005-2006 seed set initiation progressed from south to north, however the next year, Pennsylvania populations set seed earlier than either Delaware location. Location and treatment significantly affected final plant height (P9) except for Spiraea treated with sulfentrazone 4F at 2X and 4X doses (vigor of 8.9 and 7.3, respectively). Spiraea was the only species injured by the second application of sulfentrazone 4F. At 4 WAT-1 following V-10142 treatments, severe injury occurred on Spiraea (7.6 to 8.3) and burning-bush (5.1 to 7.6), and lesser injury on Arborvitae spp. (1.3 to 3.3) and Rhododendron (0.7 to 2.3). The second application of V-10142 caused additional injury to all plants. By the final evaluation on October 4 (12 WAT-2), plant vigor ratings were lowest for Spiraea (1.3 to 0.2) and highest for arborvitae (9.6 to 6.9). No weeds were present in containers on the herbicide application dates. Herbicidal efficacy of halosulfuron was not evaluated. Neither sulfentrazone nor V10142 treatments were effective at preventing horseweed (Conyza canadensis). Sulfentrazone treatments did not prevent smallflowered bittercress (Cardamine parviflora) or northern willowherb (Epilobium ciliatum). 36

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UPDATE ON 2006 WEED SCIENCE RESEARCH IN THE IR-4 ORNAMENTAL HORTICULTURE PROGRAM. C.L. Palmer and J. Baron, IR-4 Project, Rutgers Univ., Princeton, NJ. ABSTRACT The 2006 IR-4 Ornamental Horticulture Research Program sponsored crop safety testing on four different products (SedgeHammer, Sulfentrazone 0.2G, Sulfentrazone 4F, and V-10142) for over-the-top applications on various ornamental species. The program also sponsored research for applications of SureGuard on select ornamental species prior to breaking dormancy. Thirty-six different species were tested with SedgeHammer; preliminary results indicate 19 of these exhibited some level of negative impact with over-the-top applications. Sulfentrazone 0.2G was applied to 41 ornamental species with 7 exhibiting some phytotoxicity. Sulfentrazone 4F was compared with Sulfentrazone 0.2G on 30 species with 11 crops showing phytotoxicity in preliminary results. Forty-four species were examined for injury with over-the-top applications of V-10142; 25 exhibited phytotoxicity. SureGuard was applied as a dormant over-the-top application to 19 ornamental species and was injurious on seven. The results from this research will aid in the development of the labels for these products and will help growers and landscape care professionals make more informed product choices.

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2006 WEED MANAGEMENT TRIALS IN CHRISTMAS TREES. J.F. Ahrens, Connecticut Agric. Experiment Sta., Windsor. ABSTRACT Several field experiments were conducted with older and new herbicides in attempts to improve our knowledge of weed management options in Christmas tree plantings. Trees were sprayed over the top at 30 gal/A. Randomized complete block designs with four replications and three to six plants per plot were standard. The 2006 season in CT was characterized by an extremely wet May and June and a dry July which resulted in a major summer outbreak of annual weeds regardless of early spring preemergence treatments. For the fourth season, we evaluated Westar, a 1:10 ratio of sulfometuron methyl and hexazinone, as well as a 1:20 ratio. Westar at 8 oz/A (sulfometuron 0.5 oz ai/A and hexazinone 5.4 oz ai/A) gave excellent control of quackgrass (Elytrigia repens L.) and at 12 oz/A caused no injury to established Douglas fir (Pseudotsuga menziesii). Comparisons of fall versus April applications of sulfometuron plus hexazinone confirmed that fall applications give poor control of summer annual weeds. Adding non-ionic surfactant or glyphosate (Roundup Original) at 1 pt/A to dormant applications did not affect injury to Fraser fir (Abies fraseri). Control of large crabgrass (Digitaria sanguinalis (L.) Scop) was improved by increasing the rate of hexazinone in the mix to 7.5 oz ai/A, but, in 2006, crabgrass control in late season was poor at all rates. Westar alone or plus added hexazinone is a good option for Christmas tree plantations but we will suggest it primarily for conifers established one or more seasons in the field. In another experiment, asulam at 4, 6, or 8 lb ai/A, on June 30, controlled emerged large crabgrass with no injury to actively growing Fraser fir. Asulam could be useful for postemergence control in transplant beds or in the field. V-10142 75 WG (Valent U.S.A. Corp.) at 0.5 to 2.0 lb ai/A, halosulfuron 75 WG at 0.75 to 3.0 oz ai/A and sulfentrazone 4F at 0.125 to 0.5 lb ai/A were evaluated for phytotoxicity in Douglas fir and Fraser fir plantations in IR-4 trials. None injured the dormant conifers in April, but when reapplied over actively growing trees in June, 8 weeks later, halosulfuron injured Douglas fir, and V-10142 and halosulfuron injured Fraser fir. Sulfentrazone, in June, caused little injury at 0.125 lb ai/A but did not control crabgrass or common ragweed (Artemisia artemisifolia L.).

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GROUND COVER SUPPRESSION IN NORTH CAROLINA FRASER FIR PRODUCTION. D. Hundley, Avery County Cooperative Extension Center, Newland, NC and J.C. Neal, North Carolina State Univ., Raleigh. ABSTRACT Approximately one half of Fraser fir growers in Western NC are using a practice called "chemical mowing" for ground cover management. The practice has resulted in widespread groundcover dominated by native white clover, nimblewill, and a variety of low-growing forbs that effectively suppress undesirable weed species. In most cases two applications of glyphosate per year are adequate once the native groundcover has developed. Economic benefit has been substantial. At less than $4/A per application for glyphosate and an average labor cost of $10 -$12/A, the overall cost has been reduced greatly from previous weed control strategies. The groundcover establishment has provided many advantages including soil stabilization and beneficial insect habitat in Fraser fir production. One of the challenges is the need for glyphosate applications during the season of active growth, when Fraser fir trees are most sensitive to glyphosate. Therefore, beginning in the spring of 2001 and continuing through the fall of 2003, an on-farm research project was undertaken to determine the tolerance of Fraser fir to low rates of glyphosate applied during the growing season, and to identify the minimum glyphosate doses required for effective ground cover suppression. On-farm tests were conducted on 10 grower sites over 3 yr. During the first year, 4-12 oz glyphosate/A (Roundup Original) were tested. Weekly applications were initiated ~ April 15th and continued to August 1st. Herbicides were applied with a backpack sprayer equipped with a Teejet 8004 nozzle (17 GPA), applied as a directed spray contacting the lower 12-24 inches of the tree foliage. After 2001, research focused on lower rates (4-8 oz/A) during May 1- July 15. The number of tree growers and acreage included in the study increased substantially. The project was continued in the 2003 with the addition of new tools to increase the accuracy of the backpack application, reduce spray volume, and fine tune other features of the applications. Tree damage was rated on a subjective scale using tree grower participation. Weed suppression ratings were also documented using a subjective scale involving tree grower participation. Rates of Roundup Original at 4-8 oz/A were found to provide effective vegetation suppression without significant damage, with new growth present throughout the period. Eight oz/A provided the best control and could be used without damage except during a 6 week period of time that begins two weeks after budbreak begins, about May 15th and continuing until July 1st. During this period a 4 oz/A rate is required to avoid damage. Final equipment choice has resulted in Roundup Original or generic equivalent applied with a TQ15004 or a TK-2 with the addition of a 14 psi flow regulator (yellow). At various worker comfort levels the calibrated application will range from usually from 8 - 12 GPA, applied as a broadcast spray contacting the lower 6-12 inches of the tree foliage and full groundcover coverage.

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THE RESPONSE OF FIELD AND CONTAINER GROWN ORNAMENTALS TO SULFENTRAZONE AND FLUMIOXAZIN. M.W. Marshall and B.H. Zandstra, Michigan State University, East Lansing. ABSTRACT Field studies were conducted in 2006 to evaluate tolerance of container and field grown ornamentals to various rates of sulfentrazone and flumioxazin. Treatments included sulfentrazone at 0.14, 0.28, and 0.56 kg/ha and flumioxazin at 0.28, 0.56, and 1.02 kg/ha. An untreated control was included for comparison. Container grown ornamental species included periwinkle (Vinca minor L.), butterfly bush (Buddleia davidii 'Adonis Blue'), inkberry holly (Ilex glabra ‘Ivory Queen’), orange coneflower (Rudbeckia fulgida var. fulgida ‘Meadowbrite’), and boxwood (Buxus microphylla ‘Green Mountain’). Field grown ornamental species included burning bush (Euonymus alatus compactus), azalea (Azalea ‘Cannon’s Double’), boxwood, daylily (Hemerocallis ‘Evelyn Claar’), coral bells (Heuchera micrantha ‘Palace Purple’), hosta (Hosta fortunei 'Gold Standard'), and shasta daisy (Leucanthemum x superbum 'Snowcap'). In the container study, sulfentrazone was applied on July 15, 2006 and August 22, 2006. In the field study, sulfentrazone was applied on June 22, 2006 and July 24, 2006 and flumioxazin was applied on June 22, 2006. Experimental design was a randomized complete block design with 3 replications. Individual plot sizes were 0.6 by 0.9 m and 5.4 by 10.6 m in the container study and field study, respectively. Plant injury ratings were evaluated 7, 14, and 28 days after treatment (DAT) on a 0 to 9 scale with 0 indicating no injury and 9 equal to crop death. Herbicides were applied in water over-the-top of newly transplanted ornamentals at a carrier volume of 187 L/ha with a pressure of 207 KPa. Boxwood grown in container and the field showed very little injury to sulfentrazone and flumioxazin, regardless of the rate. Plants most sensitive to sulfentrazone included butterfly bush, orange coneflower, coral bell and daylily. In addition, daylily, Hosta, and Shasta daisy were sensitive to over-the-top applications of flumioxazin, especially at 1.02 kg/ha. Sulfentrazone injury, regardless of species, included browning of the leaves where the spray intercepted the leaf. New growth at the base of the plant did not exhibit these symptoms. Butterfly bush showed moderate injury at the 0.28 and 0.56 kg/ha sulfentrazone rate 7 DAT. By 28 DAT, injury was only apparent at the 0.56 kg/ha rate. In the field study, boxwood, Azalea, and burning bush exhibited very little response to flumioxazin and sulfentrazone, regardless of rate. At 14 and 28 DAT, daylily, Hosta, and Shasta daisy injury at 0.56 kg/ha ranged from 5.7 to 8.7, with the Hosta being the most sensitive. By the end of the trial; however, these plants had regrown and recovered to sizes not significantly different from the untreated control. In general, sulfentrazone and flumioxazin were generally safe on the container and field grown woody ornamental plants. Sulfentrazone at 0.28 and 0.56 kg/ha should be used with caution on container and field grown orange coneflower, butterfly bush, Hosta, and daylily. Since both formulations were liquids, a granular formulation maybe safer on these sensitive species.

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THE EFFICACY AND CROP TOLERANCE OF PRE AND POSTEMERGENCE APPLICATIONS OF HALOSULFURON TO CHRISTMAS TREES. L.J. Kuhns and T.L. Harpster, The Pennsylvania State Univ., University Park. ABSTRACT Over a two-year period, pre and postemergence applications of halosulfuron were made to three conifer species on five sites in Pennsylvania. At 0.33 lb ai/A, when combined with oryzalin for preemergence grass control, halosulfuron provided excellent broad-spectrum weed control. At 0.041 to 0.167 lb ai/A, when combined with oryzalin, it provided good to adequate control at three of the sites but was weak at two others. Applied prior to budbreak, there was little to no injury. Applied after budbreak, halosulfuron caused serious contact injury to the plants. However, no plants were killed and plants injured in 2005 grew well in 2006.

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THE EFFICACY AND CROP TOLERANCE OF PREEMERGENCE APPLICATIONS OF SULFOMETURON PLUS HEXAZINONE TO CHRISTMAS TREES. L.J. Kuhns and T.L. Harpster, The Pennsylvania State Univ., University Park. ABSTRACT Weed control and the tolerance of Douglas fir (Pseudotsuga menzesii (Mirb) Franco) Christmas trees to two ratios of sulfometuron and hexazinone were evaluated. Westar is a commercially formulated combination of sulfometuron and hexazinone in a 1:10 ratio, respectively. The same products were mixed in a 1:20 ratio to compare the weed control and crop tolerance of the two combinations. The rates listed in Table 1 were applied on April 20, 2006, around trees at Unangst Tree Farm, Northampton County; and Elizabeth Farms, Lancaster County; Pennsylvania. The trees at the two farms were 4-5 and 3-4 feet tall, respectively. The buds were beginning to swell and show some color at both sites. All applications were direct sprayed with a CO2 test plot sprayer, at 30 PSI in 24 GPA. An OC-02 nozzle was used and both sides of each row were sprayed, with the lower 6-12 inches of all trees intentionally contacted. The air and soil temperatures were 70-81 and 60 F, respectively. Each treatment was replicated four times with eight to ten trees per replication. Weed control and plant quality were rated on May 31 and July 18, 6 and 13 weeks after treatment (WAT). Because glyphosate and simazine had been applied to the field the previous fall, the Unangst site had very few weeds, even in the untreated plots. The predominant weeds in the control plots were common lambsquarters (Chenopodium album L.), oxeye daisy (Chrysanthemum leucanthemum L.), redroot pigweed (Amaranthus retroflexus L.), and yellow foxtail (Setaria glauca (L.) Beauv.). At Elizabeth Farms established perennial weeds and weed seedlings were present at the time of the first application. The predominant weeds were common dandelion (Taraxacum officinale Weber in Wiggers), Canada thistle (Cirsium arvense (L.) Scop.), common ragweed (Ambrosia artemisiifolia L.), redroot pigweed, yellow foxtail, yellow nutsedge (Cyperus esculentus L.), and downy brome (Bromus tectorum L.). Six WAT all treated plots at both farms exhibited almost total weed control, except those treated with sulfometuron plus hexazinone at 0.023 and 0.469 (Table 1). At 13 WAT, the treated plots at Unangst Farm were still almost totally weed free, with only a few foxtails and Johnsongrass breaking through. At Elizabeth Farms weed control ratings were lower and less consistent. The two higher rates of both ratios provided good control, but the lower rates provided marginally acceptable control. Both broadleaf and grass seedlings were emerging in all treated plots. The higher rates effectively controlled common ragweed, yellow woodsorrel, white clover, common dandelion, ox-eye daisy, redroot pigweed, and velvetleaf. Plant quality at both farms was uniformly good to excellent (Table2). Only the high rate of the 1:20 ratio, at Elizabeth Farms, significantly reduced the quality of trees. Injury consisted of some needle stunting and yellowing new growth. At Unangst Farm, tree quality improved between the first and second evaluations, suggesting some of the injury noted may have been from the fall glyphosate treatment. In conclusion, the commercially formulated mix of sulfometuron and hexazinone at the 1:10 ratio provided excellent weed control with minimal reduction to plant quality on Douglas fir.

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Table 1. Weed control ratings on Douglas Fir at Elizabeth and Unangst Farms on May 31 and July 18, 6 and 13 weeks after treatment. Treatments were direct sprayed on April 20, 2006. Weed control ratings are on a scale of 1 to 10, with 1 = no control and 10 = total control. Treatment

Elizabeth Farm May July 31 18 3.3 c 1.0 f

Unangst Farm May July 31 18 1/ 6.1 b 8.6 b

Untreated

Lb a.i./A -

Sulfometuron Hexazinone Surfactant

0.023 0.469 0.25% v/v

6.4 b

6.2 d

10.0 a

10.0 a

Sulfometuron Hexazinone Surfactant

0.035 0.70 0.25% v/v

9.6 a

8.4 a

10.0 a

9.9 a

Sulfometuron 0.047 9.7 a 8.5 a 10.0 a 9.9 a Hexazinone 0.938 Surfactant 0.25% v/v --------------------------------------------------------------------------------------------------------------------Westar 75.1WG 0.28 9.7 a 7.5 bc 10.0 a 9.9 a Surfactant 0.25% v/v Westar 75.1WG Surfactant

0.375 0.25% v/v

9.6 a

6.9 cd

10.0 a

9.9 a

Westar 75.1WG Surfactant

0.469 0.25% v/v

9.6 a

8.1 ab

10.0 a

9.9 a

Westar 75.1WG 0.562 9.7 a 8.1 ab 10.0 a 10.0 a Surfactant 0.25% v/v --------------------------------------------------------------------------------------------------------------------Flumioxazin 0.25 9.2 a 4.7 e 9.8 a 10.0 a Glyphosate 0.0625 Oryzalin 2.0 1/ Means within columns for each species, followed by the same letter, do not differ at the 5% level of significance (DMRT)

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Table 2. Plant quality ratings on Douglas Fir at Elizabeth and Unangst Farms on May 31 and July 18, 6 and 13 weeks after treatment. Treatments were direct sprayed on April 20, 2006. Plant quality ratings are on a scale of 1-10 with 1 = dead and 10 = highest quality plant. Elizabeth Farm Unangst Farm Treatment Lb May July May July a.i./A 31 18 31 18 1/ Untreated 9.8 a 9.7 ab 8.9 ab 9.8 a Sulfometuron Hexazinone Surfactant

0.023 0.469 0.25% v/v

9.3 bc

9.4 bc

8.8 ab

9.7 a

Sulfometuron Hexazinone Surfactant

0.035 0.70 0.25% v/v

9.8 a

9.6 ab

8.8 ab

9.7 a

Sulfometuron 0.047 9.0 c 9.1 c 8.8 ab 9.8 a Hexazinone 0.938 Surfactant 0.25% v/v --------------------------------------------------------------------------------------------------------------------Westar 75.1WG 0.28 9.8 a 9.8 ab 8.9 ab 9.9 a Surfactant 0.25% v/v Westar 75.1WG Surfactant

0.375 0.25% v/v

9.5 ab

Westar 75.1WG Surfactant

0.469 0.25% v/v

9.8 a

9.7 ab 10.0 a

8.7 ab

9.8 a

8.6 b

9.9 a

Westar 75.1WG 0.562 9.5 ab 9.8 ab 8.9 ab 9.7 a Surfactant 0.25% v/v --------------------------------------------------------------------------------------------------------------------Flumioxazin 0.25 9.8 a 9.8 ab 9.2 a 9.7 a Glyphosate 0.0625 Oryzalin 2.0 1/ Means within columns for each species, followed by the same letter, do not differ at the 5% level of significance (DMRT)

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HERBICIDES AS ALTERNATIVES TO METHYL BROMIDE FOR WEED CONTROL IN CONIFER SEEDLING BEDS. D.A. Little, M.W. Marshall, Michigan State Univ., East Lansing, R.J. Richardson, North Carolina State Univ., Raleigh, and B.H. Zandstra, Michigan State Univ., East Lansing. ABSTRACT The removal of methyl-bromide (MeBr) from the market has left some Christmas tree growers looking for alternatives for weed control. In 2004 and 2005, a field study was conducted at the Michigan State University Southwest Research and Extension Center located near Benton Harbor to evaluate herbicides as alternatives to MeBr for weed control in conifer seedling production. In early June 2004, a standard treatment of MeBr:chloropicrin (98:2) was applied at a rate of 392 kg/ha. Treatments tested were flumioxazin (0.28 kg/ha), granular oxadiazon (2.24 kg/ha), oxyfluorfen (1.12 kg/ha), oxyfluorfen plus dithiopyr (0.28 kg/ha), oxyfluorfen plus metolachlor (1.68 kg/ha), mesotrione (0.28 kg/ha), metolachlor plus mesotrione, metolachlor plus trifloxysulfuron(0.008 kg/ha), metolachlor plus rimsulfuron (0.03 kg/ha), and an untreated control. Herbicide treatments were applied over top two-year old Fraser fir (Abies fraseri) and eastern white pine (Pinus strobus) in mid-June of 2004 and 2005. Weeds present included common ragweed (Ambrosia artemisiifolia), common lambsquarters (Chenopodium album), large crabgrass (Digitaria sanguinalis), and carpetweed (Mollugo verticillata). Crop injury and weed control were visually rated on a 0-100% scale, with 0% equal to no crop injury or no weed control and 100% equal to complete crop death or weed control. Visual ratings were made monthly for four months after treatments. Tree height measurements were collected at the end of each growing season. Weed control was similar in all treatments including MeBr, except granular oxadiazon and metolachlor plus rimsulfuron which failed to control large crabgrass and carpetweed, respectively. In 2004, significant visual injury was observed on eastern white pine, one and three months after treatments containing metolachlor were applied, and in 2005, metolachlor and mesotrione significantly reduced eastern white pine height. In 2005, flumioxazin, metolachlor plus trifloxysulfuron and metolachlor plus mesotrione caused significant visual injury was seen on Fraser fir three months after treatment; however, treatments did not significantly impact tree heights.

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EVALUATION OF PROLINE-LINKED PENTOSE PHOSPHATE PATHWAY IN CREEPING BENTGRASS. D. Sarkar, P. Bhowmik, Y.I. Kwon, and K. Shetty, Univ. of Massachusetts, Amherst. ABSTRACT Creeping bentgrass (Agrostis palustris Huds.) is an important cool-season turfgrass species in North America. It is used widely in putting greens, tees, bowling greens, and in grass tennis courts. Abiotic and biotic stresses are major hindrances for normal performance of the cool-season turfgrass. Under stress conditions plants produce reactive oxygen intermediates (singlet oxygen, etc.) within cells. Antioxidant defense systems scavenge reactive oxygen species and protect cells against oxidative stress injury. Plant phenolics play important role in this defense mechanism by providing UV protection, antifungal, antiviral, antibacterial, antifeedant and antimitotic activity. Phenolic antioxidants can either trap the free radicals or scavenge them through series of coupled antioxidant enzyme defense system. Proline plays a significant role in plant under stress condition by regulating redox and hydride ion-mediated stimulation of pentose phosphate pathway. Shetty (1997) proposed a role for proline-linked pentose phosphate pathway (PLPPP) in stimulating phenolic metabolites in plants. Proline is synthesized from glutamate through series of reduction reactions, and in this process pyrroline-5carboxylate (P5C) and proline function as a redox couple and are known to be metabolic regulators. The proline, through reactions of proline dehydrogenase (PDH), can enter mitochondria and support oxidative phosphorylation (instead of NADH). The reduction of P5C provides NADP+, which is the co-factor for glucose-6-phosphate dehydrogenase (G6PDH), an enzyme that catalyzes the rate-limiting step of the pentose phosphate pathway. Proline-linked pentose phosphate pathway can stimulate both shikimate and phenylpropanoid pathways. Since, genetic heterogeneity in cross pollinated plant causes inconsistency in phenolic profiles, and related antioxidant enzyme response, screening of single seeded clonal lines is important to select an elite clonal line with superior phenolic profile and protective response. The objectives of this study are i) to understand the role of proline-linked pentose phosphate pathway for phenolic antioxidant production in creeping bentgrass, and ii) to evaluate overall antioxidant response system of creeping bentgrass. Single seeded creeping bentgrass plants (20 lines) were grown in 4.5 cm plastic pots with sand based soils and kept in growth chamber at 27 C (day/night), and 12-h photoperiod conditions. Turf was watered daily, mowed, and fertilized weekly. Shoots were collected and analyzed repeatedly for G6PDH, PDH, SDH (succinate dehydrogenase), CAT (catalase), GPX (guaiacol peroxidase), SOD (superoxide dismutase), DPPH (antioxidant activity), total phenolic, total protein, and chlorophyll. HPLC analyses of proline and phenolic profile were also undertaken. Results showed significant differences in PLPPP related enzymes such as G6PDH, and PDH among twenty creeping bentgrass lines. Similar trends were observed in case of antioxidant enzymes, like SOD, and GPX. Antioxidant activity (DPPH), and chlorophyll content also varied, but total phenolic, SDH, and CAT showed similar results in all twenty lines. Differences in activity of G6PDH, PDH, SOD, and GPX among the clonal lines provide clues to the significance of proline-linked pentose phosphate pathway in selected creeping bentgrass clonal lines.

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GENERIC PLANT GROWTH REGULATORS AND HERBICIDES IN TURF: HOW DO THEY COMPARE? T.W. Gannon and F.H. Yelverton, North Carolina State Univ., Raleigh. ABSTRACT Recently, several generic herbicide and plant growth regulators have been formulated and have been or will likely be registered for use in turfgrass environments. Minimal research has been completed looking at the efficacy of these herbicides and plant growth regulators compared to proprietary products. Therefore, some concern exists if these products perform similarly or if differences exist. Research trials were initiated to evaluate several generic herbicide and plant growth regulator formulations to determine if they performed similarly to proprietary products. Generic formulations of prodiamine, oxadiazon, and oryzalin were evaluated for preemergence control of smooth crabgrass (Digitaria ischaemum), while dithiopyr and quinclorac were evaluated for early postemergence control of smooth crabgrass. Additionally, generic formulations of trinexapac-ethyl were evaluated for foliar suppression of 'Tifsport' bermudagrass. All generic products were compared to proprietary labeled herbicides or plant growth regulators. Data collected from these trials indicates evaluated generic herbicides and plant growth regulators performed similarly to proprietary products as no differences existed within evaluated parameters. Throughout each of the research trials, no significant reductions in smooth crabgrass control were observed. Likewise, bermudagrass foliar suppression was consistent with each formulation of trinexapac-ethyl. These data indicate generic herbicides and plant growth regulators may offer a viable solution in select turfgrass environments.

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ANNUAL BLUEGRASS AND DOLLAR SPOT CONTROL AS INFLUENCED BY HERBICIDES AND PLANT GROWTH REGULATORS. S.J. McDonald, Turfgrass Disease Solutions LLC, Pottstown, PA, M.A. Fidanza, The Pennsylvania State Univ., Reading, and J. Fanok, Brookside Country Club, Pottstown, PA. ABSTRACT Bispyribac-sodium was released in 2004 and labeled for control of Poa annua (L.) and Poa trivialis (L.) in creeping bentgrass (Agrostis stolonifera L.) and perennial ryegrass (Lolium perenne L.) fairway turf. Research has shown that bispyribac-sodium has the potential for Poa annua and Poa trivialis management and that optimal time C. to apply this product may be when the average ambient air temperatures is 18 Golf course superintendents frequently apply other herbicides and plant growth regulators prior to this optimal time and information regarding possible interactions of these chemicals with bispyribac-sodium is warranted. This study was conducted on a fairway maintained at 1.3 cm height, located in southeastern Pennsylvania, and comprised of approximately 92 to 96% creeping bentgrass and 4 to 8% Poa annua. Treatments include: dithiopyr alone (0.425 kg ai/ha), dithiopyr (0.425 kg ai/ha) followed by bispyribac-sodium (0.075 kg ai/ha) at 38 and 51 days later, trinexapac-ethyl alone (0.047 kg ai/ha), trinexapac-ethyl (0.047 kg ai/ha) followed by bispyribac-sodium (0.075 kg ai/ha) at 13 and 26 days later, paclobutrazol (0.105 kg ai/A) alone, and paclobutrazol (0.105 kg ai/A) followed by bispyribac-sodium (0.075 kg ai/ha) at 13 and 26 days later. Treatments were applied using a CO2-powered backpack sprayer calibrated to deliver 408 gal water per hectare at 250 kPa. Data were subjected to analysis of variance and significantly different means were separated using Fisher's least significance different test at P ≤ 0.05. Plots were rated for percent plot area covered by Poa annua, treatment-induced injury to creeping bentgrass and Poa annua, overall turfgrass quality, and dollar spot (Sclerotinia homoeocarpa F.T. Bennett) severity. No statistically significant differences were observed with Poa annua control or injury when examined among plots treated with a plant growth regulator or herbicide followed by bispyribac-sodium. Plots treated with dithopyr alone, trinexapac-ethyl alone, or paclobutrazol alone had little effect on Poa annua population, however, all plots treated with bispyribac-sodium exhibited a statistically significant reduction in Poa annua. Also, consistently less dollar spot severity was observed in those plots treated with bispyribac-sodium. However, a slight decrease in dollar spot severity was observed in plots treated with the paclobutrazol or trinexapac-ethyl followed by bispyribac-sodium when compared to plots treated with bispyribac-sodium alone. Data from this field study indicates there were no negative effects from pretreating a mixed stand of creeping bentgrass and Poa annua with dithiopyr, trinexapacethyl or paclobutrazol when followed by bispyribac-sodium. All bispyribac-sodium treatments effectively controlled Poa annua and little injury was observed to the creeping bentgrass.

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AUTUMN PREEMERGENCE AND SPRING POSTEMERGENCE CONTROL OF MOUSEEAR CHICKWEED AND CRABGRASS IN TURF. P.H. Dernoeden and J. Fu, Univ. of Maryland, College Park. ABSTRACT Mouseear chickweed (Cerastium vulgatum) and smooth crabgrass (Digitaria ischaemum) are common problematic weeds in Maryland lawns. Preemergence herbicides were evaluated for control of both weeds in tall fescue (Festuca arundinacea) and involved single herbicide applications on either 4 November 2005 or 31 March 2006. A postemergence trial also was conducted in April 2006 and targeted primarily mouseear chickweed, however, there was some corn speedwell (Veronica arvensis) evenly distributed throughout the study area. In both studies, plots were 5 ft by 5 ft and arranged in a randomized complete block with four replications. Weed cover was assessed visually on a 0 to 100% linear scale. Data were subjected to analysis of variance and significantly different means were separated using Fisher’s LSD at P ≤ 0.05. Soil was a Keyport silt loam with a pH of 5.7 to 6.0. Sprayable herbicides were applied in 50 GPA using a CO2 pressurized (35 psi) backpack sprayer. Granulars were applied by shaker bottle. In the preemergence study, mouseear chickweed was controlled effectively by sprayable formulations of prodiamine 65WG, dithiopyr 40WP and pendimethalin 3.8CS applied on 4 November (Table 1). Dithiopyr 0.21 G (0.5 lb ai/A) and prodiamine 0.25G (0.75 lb ai/A) applied 4 November appeared to reduce mouseear chickweed levels (4.0 to 4.8%) versus the untreated control (10%), but the difference was not significant. Treatments applied in the spring had little or no effect since mouseear chickweed had emerged prior to 31 March. Smooth crabgrass pressure was low and all treatments reduced crabgrass levels significantly when plots were evaluated 8 September 2006 (Table 1). Highly effective crabgrass control (≤ 2% crabgrass cover) was provided by dithiopyr 0.21G (0.5 lb ai/A) and prodiamine 65WG (0.75 lb ai/A) applied 4 November 2005 and dithiopyr 0.21G (0.5 lb ai/A), prodiamine 0.20G (0.5 and 0.75 lb ai/A) and prodiamine 65WG (0.75 lb ai/A) applied 31 March 2006. There were few significant differences in the level of crabgrass control among herbicide treatments. In the postemergence broadleaf study, the following herbicides were applied 13 April 2006 to an immature stand of Kentucky bluegrass (Poa pratensis): quinclorac (0.75 lb ai/A + 1% MSO); 2.4-D + triclopyr (1.5 lb ai/A); triclopyr ester (1.0 lb ai/A); quinclorac + triclopyr ester (0.5 + 0.5 lb ai/A+1% MSO); and 2.4-D + MCPP + dicamba + carfentrazone (1.1 lb ai/A; Speedzone). Speedzone exhibited rapid and effective control of both corn speedwell and mouseear chickweed. All other treatments were ineffective. Corn speedwell and mouseear chickweed naturally declined and nearly all plants in untreated plots were dead by 22 May.

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Table 1. Autumn 2005 versus spring 2006 applied preemergence herbicides for smooth crabgrass and mouseear chickweed control in turf. Cover Mouseear chickweed

Rate Treatmentsy

Crabgrass

Lb ai/A

Timing

Dithiopyr 0.21G

0.38

4 Nov

Dithiopyr 0.21G

0.50

4 Nov

4.0 ef

1.3 cd

Prodiamine 0.20G

0.50

4 Nov

4.8 def

2.3 cd

Prodiamine 0.43G

0.75

4 Nov

10.3 b-e

2.3 cd

Prodiamine 65WG Pendimethalin 3.8CS Dithiopyr 40WP

0.75

4 Nov

0.0 f

1.0 cd

3.0

4 Nov

0.3 f

4.3 bc

0.5

4 Nov

0.1 f

6.0 b

Dithiopyr 0.21G

0.38

31 Mar

20.0 a

2.9 bcd

Dithiopyr 0.21G

0.50

31 Mar

11.8 bcd

0.8 cd

Prodiamine 0.20G

0.50

31 Mar

16.3 ab

1.0 cd

Prodiamine 0.43G

0.75

31 Mar

13.0 abc

0.6 d

Prodiamine 65WG Pendimethalin 3.8CS Dithiopyr 40WP

0.75

31 Mar

12.3 bcd

1.3 cd

3.0

31 Mar

8.3 cde

2.3 cd

0.5

31 Mar

7.3 cdef

2.8 bcd

--

--

Untreated y

14 Apr. 8 Sept. ⎯⎯⎯⎯⎯ % ⎯⎯⎯⎯ 8.5 cdez 5.8 b

10.0 b-e

20.3 a

Treatments were applied on either November 4, 2005 or March 31, 2006. Means in a column followed by the same letters are not significantly different according to Fisher’s LSD test (P≤0.05).

z

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THREE-WAY HERBICIDE COMBINATION CONTAINING FLUROXYPYR FOR POSTEMERGENT BROADLEAF WEED CONTROL IN TURF. D.L. Loughner, J.M. Breuninger and M.W. Melichar, Dow AgroSciences, Indianapolis, IN. ABSTRACT The development of formulated liquid herbicide mixtures containing fluroxypyr (1-methylheptyl (4-amino-3-5-dichloro-6-fluoro-2-pyridyloxyl) acetate) was initiated when the residential use registration was removed for all clopyralid (3,6-dichloro-2pyridinecarboxylic acid, triethylamine salt) containing mixtures. Mixtures containing fluroxypyr must provide commercial control of white clover (Trifolium repens) and other key driver weeds such as dandelion (Taraxacum officinale) and plantain species (Plantago spp.) to be accepted by lawn care companies. Results from 2002 - 2004 confirmed effective broadspectrum broadleaf weed control with the 0.25 lb ae/A rate of fluroxypyr in combination with 2,4-D, triclopyr and /or dicamba. Control was comparable to commercial standards Triplet® SF, (2,4-D + dicamba + MCPP-p) and Confront® (triclopyr + clopyralid). Field studies conducted during 2005 evaluated at 0.13 lb ae/A of fluroxypyr in combination with 2,4-D and dicamba (Escalade® 2). Performance was compared to Triplet, Chaser (2,4-D + triclopyr), Millennium Ultra® (2,4-D+dicamba+clopyralid) and a tank mix of 2,4-D ester + triclopyr ester + dicamba. Field protocols were designed to simulate a typical lawn care application program for postemergence broadleaf weed control in turf. Key program features evaluated included early season use of ester herbicide formulations changing to amines as temperatures increased and the use of high water volumes of approximately 2 gal/1000ft2. The results from 2005 field studies demonstrated that Escalade 2 effectively controlled key driver weeds such as white clover, dandelion, plantain spp. and mouseear chickweed equal to, and in some cases better than, the comparative standards. The data also demonstrated that environmental conditions and weed development stage did not significantly affect Escalade 2 performance.

Confront is a Trademark of Dow AgroSciences. Triplet, Escalade and Millennium Ultra are Trademarks of Nufarm Americas.

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A PRELIMINARY STUDY OF THE NON-NATIVE VASCULAR FLORA OF THREE COASTAL DELAWARE STATE PARKS. R. Stalter, E. Lamont, G. Grigoryan, and N. Faqeer, St. John’s University, NY. ABSTRACT The objective of the present preliminary study was to document non-native vascular flora at the three coastal Delaware State Parks: Cape Henlopen, Delaware Seashore and Fenwick Island. Monthly trips were made to the parks during the growing season of 2006 beginning in April, terminating in October. Over 450 specimens were collected. These were mounted on herbarium paper and will eventually be housed in the Batson Herbarium, University of South Carolina. The preliminary list of non-native vascular flora includes 73 species, 22% of the three parks flora. Three hundred thirty five vascular plant species have been identified as of October 15, 2006. Families with the greatest number of non-native vascular plant species were the Poaceae and Asteraceae with 13 and 11 species respectively. Plant families composed exclusively on non-native species were the Commelinaceae, Elaeagnaceae, Liliaceae, Molluginaceae and Oleaceae. INTRODUCTION Cape Henlopen State Park (CHSP) Delaware Seashore State Park (DSSP) and Fenwick Island State Park (FISP) extend from mid coastal Delaware south along the Delaware coast to the Delaware Maryland state line. Cape Henlopen State Park is separated from the mainland by the Lewes and Rehoboth Canal on its western border. Rehoboth Bay separates Delaware Seashore State Park from the mainland while an Assawomen Bay on the west separates Fenwick Island State Park from the mainland. Delaware Seashore and Fenwick Island state parks are narrow spits of land approximately 300 meters wide. From the western bay boundary east to Route 1 the topography is relatively flat with an elevation of 1 to 2 meters above mean sea level. East of Route 1, beach dunes range from approximately 5 to 10 meters in height. Inland island central dune fields at Cape Henlopen range in height from 9 m to 15 m in the central portion of the park. Route 1 dissects Delaware Seashore and Fenwick Island; disturbance i.e., mowing and roadside maintenance provides excellent habitat for aggressive weedy alien species. PLANT COMMUNITIES Six naturally occurring plant communities occur at the three state parks. These include the dune-grass dominated primary dune community, the pine oak community on stable old dunes, a transitional shrub community, an extensive-salt marsh community, an extensive brackish marsh community, and a sedge-forb dominated community on moist interdunal swales. Most non-native species occupy disturbed sites including maintained roadsides and gardens around habitations.

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CLIMATE The climate of Coastal Delaware is milder than that of sites directly northward or inland. Detailed climatological data for Lewes, Delaware where Cape Henlopen is located found in the monthly publication of the National Oceanic and Atmospheric Administration1. Mean annual temperature at Lewes is 56.1oF (13.3oC), and the annual precipitation is about 44.9 inches (1140 mm). The average length of the frost-free period at the coastal parks exceeds 200 days. Nor’easters may occur from late fall to mid spring. Though not as potentially severe as hurricanes, nor’easters may cause dune damage from strong northeast or east winds. Strong winds may account for unusually high tides that produce severe dune erosion. Drought is frequent and may be especially injurious to vegetation if it is prolonged and occurs during the growing season. Fenwick island has the states’ highest minimum temperature, 31oF (-0.4oC), and the state’s lowest annual snowfall, 4.01 inches (101.9 mm). METHODS Collecting trips were made to the study areas approximately once a month during the growing seasons from April 2006 through October 2006. Objectives for each trip included the collection of voucher specimens and accumulation of information on abundance and apparent habitat preference for each species. Classification and determination of non-native status of vascular plant species were according to Gleason and Cronquist2 and Bailey3. RESULTS AND DISCUSSION The flora of Delaware is composed of 2,175 species of which 610 are not native4. Dicots, 1,411 taxa, are more numerous than monocots (669 species). The Asteraceae, Poaceae and Cyperaceae are the largest families in the flora with 238, 237 and 237 species respectively. The percentage of non-native species, 22 percent, of the parks’ flora, was slightly less than the states’ as a whole. Grasses (Poaceae) and composites (Asteraceae) contain the greatest number of species at the state parks, which is similar to the state's largest plant families. Seventy three non-native vascular plant species have been identified at the three coastal Delaware state parks. Dicots (55 species) were more numerous than monocots (17 species). The total number of vascular plant species collected from April through October 15, 2006 includes 335 species in 183 genera in 92 families. Non-native species composed 22 percent of the flora. The greatest number of non-native species were found in the Poaceae (n= 13) and the Asteraceae (n= 11) (Table 2). Five families were composed exclusively of non-native taxa: Commelinaceae (1/1), Elaeagnaceae (2/2), Liliaceae (3/3), Molluginaceae (1/1), and Oleaceae (1/1). Several alien taxa, Celastrus orbiculatus, Eragrostis curvula, and Phragmites australis, pose a threat to native vascular plants. Celastrus may grow up and over

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native species, covering and smothering them. Eragrosits curvula has become well established along sandy roadsides, especially at Cape Henlopen where it out competes native species and forms nearly pure stands. Phragmites australis was well established at wet sites, especially along the shores of Assawomen Bay. University of Maryland scientists have identified 5 non-native varieties of Phragmites. These are more aggressive than the single native North American variety. Additional aggressive non-native species are Carex kobomugi, Elaeagnus angustifolia, E. umbellata, and Lythrum salicaria. Carex kobomugi is well established locally on coastal dunes, especially on the ocean-facing primary dune where wind deposits salt on vegetation. When conditions are favorable C. kobomugi forms nearly pure stands. Carex kobomugi has been reported in the coastal dunes at Sandy Hook, New Jersey, by Stalter in l975. In his l980 publication, Stalter presented historical invasion information of C. kobomugi on the Untied States east coast. Carex kobomugi may have been present at Island Beach State park, New Jersey in the l920's. It was reported at Virginia Beach, Virginia in l949, and at the public beach at Norfolk in 1966. It was also reported at Cedar Island, Virginia in l979 and at Fisherman Island, Virginia in the l970's. Stalter and Lamont (unpublished) have observed C. kobomugi on the ocean facing side of the primary dunes at Back Bay National Wildlife Refuge and False Cape State Park in southeast Virginia in the l990's. Elaeagnus spp., Russian Olive, generally occupies grassy fields. Elaeagnus angustifolia is common at Cape Henlopen State Park.. Selective cutting followed by the application of herbicide to cut stems should kill Elaeagnus and may prevent this shrub from dominating fields at Delaware’s coastal parks. Lythrum salicaria was present in small numbers at the moist interdunal swales at Fenwick Island, State Park. Populations of L. salicaria should be treated with herbicide and eradicated. If not treated, L. salicaria may become more abundant at moist habitats in the future, and pose a threat to the native vascular plant species that grow there. LITERATURE CITED 1. Garwood, A. N. 1996. Weather America Milpitas, California 217-223. 2. Gleason, H. A. and A. Cronquist, 1991. Manual of Vascular plants of Northeastern United States and Adjacent Canada. New York Botanical Garden, New York. 910 pp. 3. Bailey L. H., 1949. Manual of Cultivated Plants. Macmillan, New York. 1116 pp. 4. McAvoy, W.A. and K.A. Bennett. 2001. The Flora of Delaware. An annotated checklist. Delaware Heritage Program, Smryna, Delaware. 265 pp. 5. Stalter, R. l980. Carex kobomugi Ohwi at Sand Hook, New Jersey. Bull. Torrey Bot. Club 107:431-432.

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Table 1. A preliminary summary of the native and non-native vascular plant species at 3 coastal Delaware State Parks. Feen Ferns Gymnosperms Allies Families 1 6 2 Genera 1 6 2 Species 1 7 5 Introduced Species 0 0 1 Native-Species 1 7 4

Dicots

Monocots

Total

70 155 213 55 158

13 56 109 17 92

92 220 335 73 263

Table 2. Plant families with large numbers of non-native vascular plant species and families exclusively composed of non-native species. Family Asteraceae Commelinaceae Elaeagnaceae Liliaceae Molluginaceae Oleaceae Poaceae

Number of Alien Taxa 11/39 1/1 2/2 3/3 1/1 1/1 13/43

Percent Alien Taxa 28 100 100 100 100 100 30

Table 3. A list of aggression or potentially aggressive non-native vascular plant species at 3 coastal Delaware state parks: Cape Henlopen, Delaware Seashore and Fenwick Island. Species Carex kobomugi Celastrus orbiculatus Elaeagnus species Eragrustis curvula Lythrum salicaria Phragmites australis

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EFFECTS OF BUCKWHEAT RESIDUE ON EMERGENCE AND EARLY GROWTH OF EIGHT WEED SPECIES. V. Kumar, D.C. Brainard, and R.R. Bellinder, Cornell University, Ithaca, NY. ABSTRACT Cover crops and their residues improve soil health and suppress weeds. Buckwheat is a rapidly growing, summer annual cover crop that is widely grown by organic farmers in the Northeast, but little is known about the effects of buckwheat residue on weed suppression. The objectives of this research were (1) to evaluate the effects of buckwheat residue on emergence and early growth of eight weeds, and (2) to evaluate the possible role of nitrogen and allelochemicals in the suppression of sensitive weed species by buckwheat residue. To achieve these objectives, both field and growth chamber experiments were conducted in 2005 and 2006. For growth chamber trials, field-grown buckwheat was mowed and incorporated 40 days after planting. Soil was taken from plots with and without buckwheat residue 0 and 15 days after incorporation. Seeds of four summer annuals: Powell amaranth (PA); hairy galinsoga (HG); barnyardgrass (BYG); and common purslane (CP), and four winter annuals: yellow rocket (YR); corn chamomile (CCM); common chickweed (CK); and shepherd's purse (SP) were sown in pots and both emergence and growth were monitored daily for 20 days. The possible role of nitrogen in suppression of three sensitive species (PA. CCM, and SP) was tested by applying 0, 40, 80, and 160 kg/ha N to both buckwheat and bare ground pots. To determine the possible role of allelochemicals in weed suppression, a separate growth chamber study was conducted in which activated carbon (50ml/l) was applied to weeds grown in both buckwheat (greenhouse grown) and bare soil pots. In 2005, fresh buckwheat residues significantly reduced the emergence (36 to 74%) and biomass (36 to 90%) of all weed species except barnyardgrass. After 15 days, only PA suppression occurred. In 2006, fresh buckwheat residues suppressed emergence of only three species (PA, CP, CK) either had no effect or enhanced early growth of all eight weed species. Addition of N overcame the suppression of emergence and growth of CCM and SP but not that of PA. For PA, buckwheat residue suppressed emergence in the absence of activated carbon (p=0.053), but had no effect on emergence in the presence of activated carbon (p=0.46). In field trials conducted in 2006, PA, BYG, CK, and SP were sown in bare soil and buckwheat plots, immediately after buckwheat incorporation. Emergence of PA, CK, and BYG was reduced under buckwheat plots compared to bare soil by 72, 45, and 20%, respectively, but had no significant effect on SP. The preliminary results suggest that CCM and SP are suppressed by buckwheat residue due to lack of available nitrogen, whereas allelopathy may play an important role in suppressing PA emergence. Ongoing research will examine (i) nitrogen dynamics following buckwheat incorporation to further elucidate the role of nitrogen in weed suppression and (ii) the potential role of fungal pathogens in suppression of emergence of sensitive species.

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EVALUATION OF VARIOUS TRICLOPYR, CARFENTRAZONE-ETHYL, AND GLYPHOSATE COMBINATIONS POST-APPLIED ON JAPANESE KNOTWEED, INCLUDING THE EXPERIMENTAL HERBICIDE F-4113. A.Z. Skibo and M.A. Isaacs, Univ. of Delaware, Newark. ABSTRACT A field study was conducted over 2005-2006 to evaluate the single season efficacy of selected POST-applied triclopyr, carfentrazone-ethyl, and glyphosate combinations on Japanese knotweed (Polygonum cuspidatum syn fallopia japonica syn reynoutria japonica). Data collected included percent visual control (0-100%) at 7, 14, 21, and 28 DAT, fresh weights consisting of all above ground biomass, taken as three m2 sub-samples per plot, were collected 28 DAT and 218 DAT (30 DAE) and weighed, then dried to a constant moisture and dry weights were recorded. Data were subjected to generalized linear model (GLM). Treatment means were separated using Duncan's multiple range test at the 0.05 level of significance. There was no significant difference between the herbicide treatments of triclopyr plus carfentrazone-ethyl with COC (0.56 and 0.28, 0.093 kg ai/ha, 1% v/v respectively), 91% and 88% control 28 DAT respectively, the combinations of triclopyr plus carfentrazone-ethyl plus mesotrione with COC (0.14, 0.093, 0.105 kg ai/ha, 1% v/v respectively), 81% control 28 DAT, and the prepackaged mixture of glyphosate and carfentrazone-ethyl with COC (5.6, 0.22 kg ai/ha, 1% v/v, respectively), 73% control 28 DAT. Slightly less control was obtained when applying triclopyr alone with COC (0.56 Kg ai/ha, 1% v/v respectively). The treatments providing the best control 218 DAT/30 DAE were the combinations of glyphosate plus carfentrazone-ethyl with COC (5.6, 0.22 kg ai/ha, 1% v/v) and all three glyphosate treatments (1.85, 3.1, 3.65 kg ai/ha). There was no significant difference between rates of glyphosate applied alone suggesting that the lowest rate, 1.85 kg ai/ha, is adequate for the control of Japanese knotweed. All of the other treatments were relatively ineffective in controlling Japanese knotweed regrowth the following season (2006).

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0.181bcd 0.137cde 0.162cde 0.189bc 0.172bcde 0.192bc 0.261a 0.188bc 0.195bc

80.7ab 73.7abc 69.0abc 71.3abc 70.7abc 51.3bcd 43.3cde 35.0de 20.0ef

0.235ab 0.06527

0.120de

90.7a

0.0f 30.7

0.116e

28 DAT -kg/plot-

88.0a

28 DAT -%-

0.636a 0.2279

0.2530b 0.00c 0.00c

0.246b 0.00c

0.00c 0.269b

0.307b 0.00c

0.348b

0.262b

30 DAE -kg/plot-

2

58

Abbreviations: DAT, days after treatment, DAE, days after emergence (07 MAY 2006) Means followed by the same letter are not significantly different according to Duncan’s multiple range test at the 0.05 level of significance 3 Japanese knotweed control was estimated visually 7, 14, 21, and 28 DAT. 4 Japanese knotweed biomass, taken as three 1meter2 sub-samples per plot, were collected 28 DAT and 218 DAT/ 30 DAE. Biomass dry weights were representative of percent reduction when compared to the control. 5 Treatments included a non-ionic surfactant at 2.5% v/v 6 Treatments included crop oil concentrate at 1% v/v

1

-----

0.56 0.093 0.28 0.093 0.56 0.093 0.106 5.8 0.22 5.68 0.56 0.56 0.106 3.1 0.28 0.106 3.65 1.85

Triclopyr + carfentrazone-ethyl6 Triclopyr + carfentrazone-ethyl6 Triclopyr + carfentrazone + mesotrione6 F-4113 Carfentrazone-ethyl + glyphosate1 Triclopyr1 Triclopyr + mesotrione6 Glyphosate Triclopyr + mesotrione6 Glyphosate Glyphosate

Untreated Control LSD0.05

Rate -kg ai/ha-

Herbicide treatment

Japanese knotweed control 28 DAT and biomass reductions 28 DAT and 218 DAT/ 30 DAE. 2005-2006.1, 2 Japanese knotweed control1 Japanese knotweed dry weights 1

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HURRICANES, AGING FORESTS, AND OVERABUNDANT WHITE-TAILED DEER: FACILITATORS OF INCREASED EXOTIC PLANT INVASION. J.L. Snitzer, H.M. McNett, K.L.A. Caraher, J. Bailey, Hood College, Frederick, MD, K.L. Kyde, Maryland Dept. of Natural Resources, Annapolis, and D.H. Boucher, Hood College, Frederick, MD. ABSTRACT Based on results in Eastern deciduous forests in Central Maryland damaged by hurricanes Isabel, Ivan and Katrina, the following observations were made: 1. Forests in the Mid-Atlantic States are becoming increasingly susceptible to windthrow as they age and as tree size increases. 2. Exotic invasive plants are favored by the canopy gaps and soil disturbance created by windthrow. 3. Browse by white-tailed deer reduces the percent cover of native plants and increases the percent cover of exotic plants following storm damage. The combination of selective deer browse and extensive colonization of stormdamaged forest by exotic plants may be altering forest regeneration.

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ENHANCED TOLERANCE TO WEED COMPETITION: EFFECTS OF CROP AND SOIL MANAGEMENT IN A LONG-TERM CROPPING SYSTEMS TRIAL. M.R. Ryan, The Pennsylvania State Univ., University Park and The Rodale Institute, Kutztown, PA, D.A. Mortensen, S.B. Mirsky, The Pennsylvania State Univ., University Park, D.O. Wilson, R.M. Seidel, and P.R. Hepperly, The Rodale Institute, Kutztown, PA. ABSTRACT Long-term cropping systems trials systems provide unique opportunities to explore the effect of crop and soil management on crop-weed competition. The Farming Systems Trial (FST) was initiated in 1981 and compares a conventional management system with a corn-soybean rotation to two organic management systems. One organic system represents a dairy operation with a corn, soybean, wheat, and hay rotation, and uses manure as a nitrogen source for corn. The other organic management system represents a cash corn, soybean, wheat system without livestock, and uses legumes as a nitrogen source. Over the 26 year history of the FST, the conventional and organic-livestock systems produced similar corn and soybean yields while the organic-legume system averaged approximately 10% lower yield (corn yields: 7460, 6718, and 7439 kg ha-1; soybean yields: 2332, 2213, 2434 kg ha-1 for the organic-livestock, organic-legume, and conventional systems respectively). At the same time the two organic systems averaged 4-5 times greater weed biomass than the conventional system. To explore the apparent increased weed tolerance in the organic systems, an experiment was conducted to determine if differences exist in crop-weed competition relationships in corn and soybean across systems. Density of mixed weed species was manipulated to achieve four levels ranging from weed free to a heavy infestation. Weed density and biomass at peak accumulation was used as a measure of weed infestation. The rectangular hyperbola model was fitted to data from each system. Crop yield loss as a function of mixed weed density was higher in the conventional system. Descriptive models of weed competition on crop yield were fit using best subsets multiple regression to determine the competition effect of individual weed species to corn and soybean yield across systems. The rectangular hyperbola model was manipulated to explore the intensity of competition of individual weed species across systems. Preliminary analysis indicates that crop and soil management system differentially influences the competitive ability of weed species. Other mechanisms responsible for overall difference in crop yield loss as a function of weed density are perceived to be soil mediated crop production capacity.

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THE ECOLOGY AND SPREAD OF INVASIVE SWALLOW-WORT SPECIES ACROSS NY STATE: DO ALLELOPATHY AND GENOTYPE PLAY A ROLE? C.H. Douglass and L.A. Weston, Cornell Univ., Ithaca, NY. ABSTRACT Pale swallow-wort (Vincetoxicum rossicum (Kleopow) Barbar.) and black swallow-wort (V. nigrum (L.) Moench) are herbaceous perennial vines introduced to the Northeastern U.S. from their native ranges in Eastern Europe and the Iberian Peninsula, respectively. While black swallow-wort can be found throughout the Northeast, from Long Island to Maine and west to St. Lawrence County in New York State, pale swallow-wort is most common in southern Ontario, Canada and Central N.Y. State, especially in the Finger Lakes region. Both species invade forest understories in unmanaged natural areas, but are becoming increasingly problematic in tree nurseries, fallow fields, and no-till cropping systems. Published reports have identified the potential allelopathic ability of these two swallow-wort species as possibly playing a significant role in their invasibility and increased competitiveness. Furthermore, numerous secondary metabolites (primarily alkaloids) with potent fungicidal or cytotoxic effects in mammalian systems have been extracted from swallow-wort foliar tissues. In order to test whether the two swallow-worts are indeed allelopathic, we designed a number of laboratory bioassays to examine the source and activity of bioactive secondary products in each species. Preliminary findings indicate up to a thirty percent decrease in root elongation of large crabgrass (Digitaria sanguinalis) seedlings when grown in the presence of seedlings of both swallow-wort species. Both swallow-wort species display a high degree of phenotypic plasticity in natural settings, particularly with respect to leaf size, shape and surface characteristics, which may be related to their ability to adapt to diverse settings. Given that the swallow-worts are prolific cross pollinators and seed producers, it is likely that introduced populations exhibit some degree of genetic diversity. We are currently examining inter- and intra-population phenotypic plasticity as well as genetic diversity in populations collected across NY, in an attempt to examine factors likely associated with invasibility. By comparing standard measures of phenotype (leaf shape index, flowering time, flower color, node number) and genetic distance between and within swallow-wort populations, we can further characterize the NY populations of both species of swallowwort. Characterization will allow us to examine the recent spread of both species and their potential species similarities and differences, including reproductive success, which may involve successful hybridization of the two species in increasingly overlapping ranges.

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EFFECTS OF PLANTING AND TERMINATION DATE ON COVER CROP BIOMASS AND SUBSEQUENT WEED SUPPRESSION USING ROLLER/CRIMPER TECHNOLOGY. S.B. Mirsky, W.S. Curran, and M.R. Ryan, The Pennsylvania State Univ., University Park. ABSTRACT Mechanical weed control with high tillage and cultivation frequency are typical weed management strategies for reduced pesticide or organic producers. Improving soil quality, namely increasing soil organic matter levels, is a goal that is frequently highlighted by producers. However, despite greater return of organic matter to the soil, the increased number of disturbances inherent to these cropping systems often results in a zero net gain or loss of soil organic matter. Rolling/crimping cover crops, as opposed to residue incorporation, has been suggested as a means of reducing tillage, weed populations, and herbicides used to control the cover crops. The objective of this experiment was to test the effects of planting and termination dates on rye (Secale cereale) cover crop biomass production and ensuing weed control. Efficacy of mechanical control of rye at different developmental growth stages was also tested. Planting of rye cultivars were seeded 10 days apart from August 25-October 15 (six planting dates and a control with no rye planting). Spring termination of cover crops occurred on 5/1, 5/10, 5/20, and 5/30. Rye biomass was sampled prior to each termination date, and weed population size was measured four and eight weeks after each termination date. Rye biomass increased with each 10 day delay in termination, and decreased with progressively later planting dates. Cover crop biomass ranged from 2150 to 11,025 kg ha-1. Weed populations densities decreased with increasing delay in cover crop termination date. Complete weed control was achieved at the May 30 termination date 8 weeks after cover crop rolling in the 2005 field site. A comprehensive characterization of the relationship between cover crop biomass accumulation, growing degree days, and subsequent weed suppression will enhance success and adoption of cover crop technology.

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EFFECTS OF FLOATING ROW COVER ON WEED EMERGENCE AND STALE SEED BED PERFORMANCE. D.C. Brainard, R.R. Bellinder and V. Kumar, Cornell Univ., Ithaca, NY. ABSTRACT Floating row covers can be valuable for season extension and for protecting crops from insects such as flea beetles. However, row covers complicate weed management since they improve conditions for germination and growth of weeds, and require removal for cultivation or herbicide applications. The objectives of this research were to (i) assess the effect of floating row covers on soil temperature and weed emergence, and (ii) to evaluate whether a stale seed bed used either alone or in combination with row cover before crop planting could reduce weed emergence after crop planting. Four field trials were conducted in central NY beginning in either late May or early July, 2005 and 2006. No crops were grown, but crop planting was simulated using a Monosem seeder. Each trial consisted of a total of six treatments arranged in RCBD. After simulated crop planting, plots were either left bare, or covered with floating row cover (Agribon 19). For each of these post-planting treatments, three pre-planting treatments were examined: (i) a conventional (CONV) treatment in which plots were harrowed immediately before simulated crop planting, (ii) a stale seed bed (SSB) treatment in which beds were prepared 2-3 wk in advance, and emerged weeds killed with Roundup (0.05 lbs ai/A) immediately before simulated crop planting, and (iii) a stale seed bed with row cover (SSB+RC) treatment, which was the same as the SSB treatment, except that plots were covered with floating row cover before simulated crop planting. Average soil temperatures (at 3 cm depth over a two wk interval) ranged from 0 to 3.5 C higher under the floating row cover compared to bare soil, with an average difference of 2.2 C. Temperature differences were highest in mid afternoon and on sunny days, reaching as much as 12 C. Higher temperatures under row covers resulted in 2- to 200-fold increases in weed emergence before simulated crop planting compared to bare soil, depending on trial and weed species. Averaged over all trials, weed emergence two wk after simulated crop planting was reduced 38% in SSB treatments, and 61% in SSB+RC treatments compared to CONV treatments. In two trials, SSB+RC treatments resulted in greater than 90% reduction in weed emergence compared to CONV controls. Our results demonstrate that (i) when used after crop planting, floating row covers can exacerbate weed management problems through stimulation of weed emergence, but that (ii) when used before crop planting, floating row covers can enhance the performance of stale seed beds and reduce emergence of weeds with the crop.

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A UNIFYING FRAMEWORK FOR SPECIES INTRODUCTIONS: THE STATE FACTOR MODEL. J.N. Barney, Cornell Univ., Ithaca and T.H. Whitlow, Cornell Univ., Ithaca, NY. ABSTRACT Synthetic quantitative models are valuable aids for predicting the behavior of complex ecosystems. Hans Jenny formed the first such model in the 1940s to describe any quantifiable soil property (s) as a function of five simple state factors: climate (cl), organisms (o), relief (r), parent material (p), and time (t). This simple 'clorpt' model allowed researchers to examine the effect of each state factor independently on any quantifiable soil property. Jack Major later adapted the ‘clorpt’ model to describe entire plant communities (V), and any property of vegetation (v). These state factor models are simple, generalizable, and amenable to empirical investigation. We have taken the concept of the state factor model and applied it to the study of incipient species introductions. The model contains five independent state factors that determine if an incipient introduction will become established, and subsequently, properties of the introduction once established. The state factors are invader autoecology (i), source habitat (s), introduced habitat (h), propagule pressure (p), and time elapsed since introduction (t). This novel model can be used to understand the enigma of introduced population success or failure in any habitat and time frame. Additionally, through manipulation of state factor variance this model can be used as a framework to explore any quantifiable property of a population (or meta-population) at any scale. We will discuss each state factor in detail, demonstrate independence among state factors, and explore uses.

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GERMINATION PATTERNS OF SWAMP DODDER SEEDS PLANTED NEAR A COMMERCIAL CRANBERRY FARM. H.A. Sandler and K. Ghantous, Univ. of Massachusetts-Amherst Cranberry Station, East Wareham. ABSTRACT Dodder (Cuscuta gronovii) is a serious weed pest in commercial cranberry that is typically controlled with preemergence herbicides, such as Casoron (dichlobenil) or Kerb (pronamide). Successful management is tied to proper timing of herbicide to recently germinated seedlings. This study was initiated to gather information on the germination patterns of dodder to facilitate timely applications. Utilizing a simple system of simulated bogs constructed in plastic containers, the germination pattern of MA dodder seed has been monitored for 9 years. In 1997, 8 cm of peat was placed in the bottom of a 5-gallon container, covered by 10 cm of sand, which was then covered with 13 cm of 50:50 sand:peat mix. In the fall of 1997 and 1998, one set of 10 containers was prepared in this fashion. On 8 Dec. 1997, 150 cc of unscarified dodder seed was placed on the top layer and incorporated into the top 1 cm of mixture. The containers were randomly arranged outside near a greenhouse, approximately 15 m from the cranberry production area. Based on the large number of germinated seedlings generated from this initial set, the seed amount was reduced to 15 cc for inoculation of the second set. The second set of containers was inoculated on 7 Dec. 1998. Pots were monitored twice weekly starting in early April until the first seedling germinated. Seedlings were counted and removed daily and less frequently during high and low germination periods, respectively. The containers were watered and weeded as needed. In 1998, over 50,000 seedlings germinated from the first set of containers, with a peak 2-week period in early May (Julian date 121-134) that generated an average of approximately 1,700 seedlings per container each wk. A second peak occurred in midJune (Julian date 163-169) that tallied an average of 372 seedlings per container. Even in early July (Julian date 184-190), an average of 30 seedlings were germinating per container. Germination was still robust for the next 3 yr, (44-66% of Year 1). By 2006, germination was ~10% of Year 1, (3,700 seedlings). Numbers were lower in the second set, but followed a similar trend. Dodder seeds apparently have a definitive peak of germination in the initial year after planting. Peaks can still be seen in subsequent years, but they are less definitive and much lower in absolute numbers. Over the course of this 9-year study, the peak germination period occurred later each year. The delay of peak germination may contribute to the difficulties growers have in managing dodder. As new seed is introduced into the system each year, its peak germination period may be different from dodder germinating from the seedbank. Since most herbicides targeting dodder can only be efficacious for a specific window of time, a portion of the population may always escape preemergence control and provide enough viable seedlings to cause substantial infestations in the vine canopy.

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BIOLOGY OF MULTIFLORA ROSE: AN INVASIVE SPECIES. P. Bhowmik, D. Sarkar, and N. Tharayil, Univ. of Massachusetts, Amherst. ABSTRACT Multiflora rose (Rosa multiflora Thunberg ex. Murray), a member of Rosaceae, is a stout, thorny, perennial shrub with arching stems. It is native to Japan, Korea, and eastern China, and has been introduced into the east coast of North America, via Japan, as an ornamental plant. During 1940-1960, this species was widely planted in the eastern US as a wildlife plant for erosion control and as a living fence. It is widely distributed throughout the US with the exception of the Rocky Mountains, the southern Coastal Plain and the desert of CA and NV (Fig. 1). Multiflora rose infests more than 45 million acres throughout the eastern US, ranging from northern TX, AK, MI, AL, and GA in the south, to the New England coast, central NY in the north, and southern MI, WI and MN. It is able to invade a large number of habitats, from hillside pastures, fence rows, right-of-ways, and roadside to forest edges and the margins of swamps and marshes. Multiflora rose can tolerate a wide range of soils and environmental conditions. It forms dense impenetrable thickets or completely takes over the pasture. It has been classified as a noxious weed in IL, KS, MD, MO, OH, PA, VA, WI, and WV. Multiflora rose primarily reproduces by seeds, but it also can sprout, and form root at the tips of arching canes that contact the ground. Mature plants may reach 3 m height and 6.5 m diameter. Stems are reddish to green, 1.5 cm in diameter and bear numerous, recurved thorns. Leaves are pinnately compound with 5 to 11 sharply toothed, ovate to oblong leaflets. Petioles are 1 to 1.3 cm long with finely dissected, usually glandular stipules. Flowers appear in large, showy, densely to sparsely flowered panicles at the ends of the branches in late May or early June. The five petals are white to pinkish, obvate and truncate. Fruit is an achene, and achenes are flattened, oval to obvoid, yellowish to tan in color and enclosed in a smooth reddish hypanthium. Each cane/stem on a large plant may contain 40 to 50 panicles, and each panicle can contain as many as 100 hypanthia or hips, and each hip, an average of seven seeds. Thus each large cane can produce 17,500 seeds, and those seeds can remain viable in soil for as long as 20 years. Birds are the primary disperser of the multiflora rose seeds, and passing through the digestive tract of birds enhances seed germination. Germination is also enhanced by stratification. Seedlings begin to appear within 60 d if the soil surface remains warm. Mechanical and chemical control methods are most widely used for multiflora rose. Repeated mowings for several years are necessary to clean heavily infested areas. July is the best time for mowing. Bulldozing, chaining, or brush hogging is often effective to knock down the large established plants. European rose chalcid (seed wasp) (Magastigmus aculeatus var. nigroflavus Hoffmeyer) and rose-rosette disease (Phyllocoptes fructiphilus Keifer), which is spread by tiny native mite are the promising biocontrol agents. Effective control of multiflora rose can be achieved by several herbicides. Glyphosate at 1 to 2% (V/V), when applied in June-July gave 95 to 100% control. Triclopyr, tebuthiuron, dicamba, picloram, and metsulfuron also gave good control of multiflora rose. Continued monitoring of this species for its new habitats, development of IWM strategies, and adoption of management options are important steps to restrict this invasive weed.

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Figure 1. Distribution of multiflora rose in USA. Source- http://plants.usda.gov

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AN OUNCE OF PREVENTION. M.J. VanGessel, Univ. of Delaware, Georgetown, D. Doohan, Ohio State Univ., Wooster, P.J. Christoffoleti, S.J.P. de Carvalho, and M. Nicolai, Univ. of São Paulo, Piracicaba, São Paulo, Brazil. ABSTRACT Prevention has been a cornerstone of weed management throughout history and arguably is the most cost-effective approach that a grower can take. However, preventive management is complex, involving integration of a group of practices and policies that avoids introduction, infestation, or dispersion of certain weed species to areas free of those species or biotypes. At the agro-ecosystem level, seed or propagule dispersion from field to field and from farm to farm needs to be recognized as an important factor that affects the whole agricultural system and should be included in comprehensive weed management planning. In the absence of human activity weeds rely upon the same natural processes for dissemination as do other plants; dispersal by wind and water, adhesion to fur or feathers, and through food webs. However, farming, trade, and human migration usually amplify the impact of these dispersal adaptations. Dispersal of weeds by human activities include plant introductions, use of infested crop seeds, movement with machinery and equipment, movement with harvested plant parts, movement with soil, animals and associated manure, and use of infested irrigation water. Manure application, irrigation water, use of plant material as organic matter (although not quantified in the literature), and use of weed seed contaminated crop seed all contributed thousands to hundred of thousands of seeds per hectare. Additional management practices (i.e., composting, addition of screens, etc.) can have dramatic impacts on reducing the number of viable seeds; however, seldom is the loss of viability 100%. The focus of a prevention program is two-fold, to eliminate the introduction of new species (or biotype) as well as reducing the number of seeds in the weed seed bank. Once a species is introduced and is allowed to emerge, become established, and produce seed, there is potential to become a significant portion of the weed seed bank in a relatively short period.

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RESPONSE OF PALE SWALLOW-WORT TO TRICLOPYR APPLICATION AND CLIPPING. K.M. Averill, A. DiTommaso, and S.H. Morris, Cornell Univ., Ithaca, NY. ABSTRACT Pale swallow-wort (Vincetoxicum rossicum (Kleopow) Barbar.) is an invasive alien vine in natural areas in many Northeastern U.S. States and Provinces of Ontario and Quebec. Since effective control of this herbaceous perennial has been previously difficult, we conducted a two-year (2005-2006) triclopyr and clipping field study in Chaumont, NY. We compared the effects of a single season (mid-June 2005) foliar application of triclopyr at the labeled rate of 1.9 kg a.e. ha-1, alone and in combination with clipping of aboveground tissue (mid-July), and the effects of clipping once (midJune) and twice (mid-June and mid-July) during the first and second seasons on pale swallow-wort stem and seedling density and percentage cover. By the end of September 2005, pale swallow-wort stem densities were significantly lower in triclopyrtreated plots (0.43 to 13 stems m-2) than in clipped-only (181 to 206 stems m-2) and unmanaged control (167 stems m-2) plots. Similarly, the percentage cover of pale swallow-wort was significantly lower in plots treated with triclopyr (6 to 13%) compared with plots subjected to clipping only treatments (76-85%) or unmanaged control plots (78%). By the end of September 2005, the percentage cover of other plant species was significantly higher in triclopyr treatments (66 to 67%) than in the clipping only treatments (11-16%) and in the unmanaged control (11%). The same differences in stem density and percentage cover were observed through August 2006. Seedling densities of pale swallow-wort varied by year and treatment. Densities were significantly greater in the clipping only and control treatments in 2005 (964 to 1207 seedlings m-2) than the same treatments in 2006 (414 to 493 seedlings m-2), but they were not significantly different in the triclopyr treatments between 2005 (114 to 207 seedlings m2 ) and 2006 (111 to 254 seedlings m-2). By the end of both the 2005 and 2006 growing seasons, in clipping only plots mature follicles were produced, however in triclopyrtreated plots no follicles were produced. Thus, the clipping only treatments, regardless of frequency, were not effective in reducing pale swallow-wort aboveground biomass, cover, or follicle production. The timing of clipping may be critical in reducing follicle production and, although further assessments are necessary, a later-season (August) clipping may be more effective. Although in this study a single application of triclopyr provided considerable control of pale swallow-wort even after two growing seasons, it is likely that repeat applications of triclopyr during multiple years would be required to achieve effective control, especially in heavily infested areas.

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HERBICIDE COMPARISON IN WET BLADE APPLICATIONS FOR SWEET GUM, TULIP POPLAR, AND RED MAPLE CONTROL. A.R. Post and J.C. Neal, North Carolina State Univ., Raleigh, and C.A. Judge, BASF, Research Triangle Park, NC. ABSTRACT Roadside and right-of-way vegetation must be managed to maintain motorist visibility and safety, and to prevent vegetation from interfering with utility lines. Traditionally, the department of transportation has used mowing or broadcast sprays of broad-spectrum herbicides to control woody vegetation on roadsides and right-of-ways. Mowing provides only temporary suppression and must be repeated every one to three years. Broadcast sprays are undesirable on right-of-ways due to the potential for offtarget impacts. An alternative herbicide application strategy is the treatment of cut stems using "wet blade" application systems such as the Diamond Wet Blade. However, little research has been conducted to compare the effectiveness of wet-blade herbicide applications on woody vegetation. This study compared the efficacy of wet blade applications of four herbicides at five concentrations each on three common, roadside woody weeds -- sweet gum (Liquidambar styraciflua), tulip poplar (Liriodendron tulipifera), and red maple (Acer rubrum). The treatments included triclopyr (Garlon 3A), metsulfuron (Escort), and glyphosate (Rodeo) at 50%, 25%, 10%, 5%, and 1% and imazapyr (Arsenal) at 10%, 5%, 2.5%, 1%, and 0.5% by volume in water. Trees were plantation-grown for this study to ensure uniform age at application. Five ml of each treatment solution was applied to the cutting blade of lopping shears and stems were cut approximately 10 cm above the ground. Treatments were applied November 30, 2005 in a randomized complete block design with 4 replications of each species. Re-growth was measured August 30, 2006. No treatment resulted in 100% mortality of all species. Sweet gum was 100% controlled by 50% triclopyr and 10% imazapyr; 25% triclopyr and 1% imazapyr each provided >90% on sweet gum. Red maple was controlled 100% by 10%, 2.5% and 1% imazapyr; and >90% by 0.5% imazapyr. No treatment provided 100% mortality of tulip poplar. Greatest tulip poplar control was observed with 2.5 to 10% imazapyr, and 10% to 50% glyphosate. Triclopyr did not control tulip poplar. This study suggests that combination treatments may be required to achieve broad-spectrum woody vegetation control with wet blade applications. _____________ Acknowledgement and Disclaimer: this research was funded by a grant from the NC Department of Transportation. The authors are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of either the North Carolina Department of Transportation or the Federal Highway Administration at the time of publication. This report does not constitute a standard, specification, or regulation.

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EVALUATION OF HERBICIDES FOR CONTROL OF MORROW’S HONEYSUCKLE USING FOLIAR TREATMENTS. J.M. Johnson, A.E. Gover, and L.J. Kuhns, The Pennsylvania State Univ., University Park. ABSTRACT As part of an ongoing research project funded by the Pennsylvania Department of Transportation, a study was established to investigate the effectiveness of several herbicides and tank mixes for controlling Morrow’s honeysuckle (Lonicera morrowii Gray, LONMO). This trial was established in a pasture near University Park, PA. Fifty shrubs were tagged and measured to determine average canopy width. The treatment volume for each shrub was derived using the calculated basal area and an application volume of 935 l/ha. The study was arranged in a completely randomized design with ten treatments and five replications. Each shrub represented a single replicate. Treatments were applied as a foliar application on June 29, 2005 using a CO2-powered sprayer equipped with a spray wand with a single XR8008VS tip. Herbicide treatments (kg ae/ha) included metsulfuron at 0.042, 0.084, or 0.13; fosamine at 4.0 or 8.1; fosamine at 4.0 plus imazapyr at 0.070; glyphosate (isopropylamine) at 3.4, alone or in combination with imazapyr at 0.07; and metsulfuron at 0.042 with the premix of dicamba at 0.28 plus diflufenzopyr at 0.11. A non-ionic surfactant1 was added to all treatments at 0.25 percent, v/v, except those containing the surfactant-loaded glyphosate. Visual ratings of percent canopy reduction were taken September 1, 2005, and July 10, 2006, 9 and 51 weeks after treatment (WAT). At 9 WAT, all treatments containing metsulfuron resulted in almost complete canopy reduction with values ranging from 97 to 100 percent. Glyphosate combinations were rated from 82 to 93 percent canopy reduction. Treatments that included fosamine were rated between 33 and 57 percent canopy reduction. At 51 WAT, LONMO treated with all rates of metsulfuron, the glyphosate combinations, and the 8.1 kg ae/ha rate of fosamine were rated between 80 and 100 percent canopy reduction. Fosamine at 4.0 kg ae/ha, alone or with imazapyr at 0.07 kg ae/ha was rated at 48 and 52 percent reduction.

1

Activator 90, Loveland Industries Inc., Greeley, CO.

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Table 1. Morrow's honeysuckle (Lonicera morrowii, LONMO) was treated with foliar herbicide applications on June 29, 2005. Visual ratings of percent canopy reduction were taken September 1, 2005 and July 10, 2006, 9 and 51 weeks after treatment (WAT). Each value is the mean of five replications. One shrub was not located during the rating at 51 WAT. Means for 51 WAT followed by the same letter are not significantly different according to Fisher's Protected LSD at p=0.05. Application LONMO canopy reduction Treatment rate 9 WAT 51 WAT kg ae/ha --------------- % ---------------untreated

---

0

0 c

metsulfuron

0.042

97

80 a

metsulfuron

0.084

100

98 a

metsulfuron

0.13

100

100 a

fosamine

4.0

33

48 b

fosamine

8.1

57

84 a

fosamine imazapyr

4.0 0.07

40

52 b

glyphosate

3.4

82

93 a

glyphosate imazapyr

3.4 0.07

93

99 a

100

96 a

20

---

metsulfuron 0.042 dicamba + 0.28 diflufenzopyr 0.11 Protected LSD (p=0.05)

72

91

EFFICACY OF GLYPHOSATE, IMAZAPYR AND TRICLOPYR FOR PHRAGMITES MANAGEMENT IN A CONNECTICUT MARSH. T.L. Mervosh, Connecticut Agricultural Experiment Station, Windsor; and D.P. Roach, All Habitat Services LLC, Madison, CT. ABSTRACT Common reed or phragmites (Phragmites australis (Cav.) Trin.) is an invasive grass that dominates many wetland areas, including freshwater and brackish marshes throughout the Northeast. This extremely tall, rhizomatous perennial displaces cattails (Typha spp.) and other native plants. The efficacy of three herbicides was evaluated in a study in a tidal marsh along the lower Connecticut River in Old Saybrook. The area was mowed in March 2005 to cut down dry standing stalks of Phragmites. Plots were arranged in a RCB design with three replicates per treatment. Plot dimensions were 20 ft x 20 ft, and untreated alleyways (10 ft) surrounded each plot. Herbicide products with aquatic use registrations were evaluated. Isopropylamine salt of glyphosate, isopropylamine salt of imazapyr, and/or triethylamine salt of triclopyr were sprayed over the top of Phragmites-dominated plots at one of three timings in 2005: June 2 (‘A’), June 24 (‘B’), or September 14 (‘C’). Herbicide treatments were prepared in 2-L bottles. Based on calibration tests before each application, bottles were filled with CO2 to a specific pressure. For the ‘A’ timing, Phragmites was an average of 4 ft tall, and herbicides were applied using a hand-held, four-nozzle spray boom with TeeJet 8003VS tips. Spray volume was 25 gallons/A. For the ‘B’ and ‘C’ timings, Phragmites was an average of 8 ft and 11 ft tall, respectively. Herbicides were applied from an elevated platform mounted on an amphibious all-terrain vehicle driven in the alleyways. Treatments were sprayed with a Hypro XT-043 boomless nozzle in two passes from opposite ends of each plot. Spray volume was 50 gallons/A. In addition to an untreated check, the following treatments were applied at all three application timings: triclopyr at 1.5, 2.25 or 3 lb ai/A; glyphosate at 2 lb ai/A; glyphosate + triclopyr (1 + 1.5 lb ai/A, or 2 + 0.75 lb ai/A); imazapyr at 0.5 lb ai/A; imazapyr + triclopyr (0.125 + 1.5 lb ai/A, or 0.125 + 2.25 lb ai/A). For the ‘A’ and ‘B’ timings, two additional treatments were included in which triclopyr at 1.5 or 2.25 lb ai/A was applied a second time to the same plots on September 9, 2005. All treatments included a non-ionic surfactant (1 qt/A) in the spray solution. Plots were evaluated periodically through September 2006 for height, relative number of stems, vigor, injury symptoms, and effects on other plants. Most treatments were more effective when applied in September 2005 (‘C’) than when applied in June 2005 (‘A’ or ‘B’). Treatments containing glyphosate and/or imazapyr were better than treatments containing only triclopyr at reducing growth in 2006. Although triclopyr suppressed Phragmites following 2005 applications, Phragmites growth the next year was reduced substantially only when glyphosate or imazapyr was combined with triclopyr. The imazapyr (0.5 lb ai/A) treatment and those containing glyphosate at 2 lb ai/A provided the best control of Phragmites in 2006. Plots will be evaluated in 2007 for Phragmites and for other plant species that emerge. Triclopyr did not perform as well in this experiment as it has in large-scale Phragmites management projects conducted by D. Roach. Application parameters such as timing, spray volume and coverage are factors that likely influence triclopyr efficacy. 73

92

EVALUATION OF HERBICIDES FOR CONTROL OF JAPANESE KNOTWEED. J.M. Johnson, A.E. Gover, and L.J. Kuhns, The Pennsylvania State Univ., University Park. ABSTRACT As part of an ongoing research project funded by the Pennsylvania Department of Transportation, a study was established to investigate the effectiveness of several herbicides and tank mixes for controlling Japanese knotweed (Polygonum cuspidatum Sieb & Zucc., POLCU). This trial was established on a well-established stand of Japanese knotweed located on an island of the Susquehanna River within Milton State Park, Milton, PA. POLCU ranging from 2.4 to 3.7 m was mowed to the ground on June 8, 2005, and 2.7 by 7.6 m. plots were laid out in a randomized complete block design with three replications. POLCU regrowth height averaged 0.8 m, and average cover ranged from 37 to 89 percent when sprayed on August 17, 2005. Treatments were applied as a foliar spray using a CO2-powered, hand-held, fixed-width boom equipped with TeeJet XR8004 VS tips delivering 281 l/ha at 172 Kpa. Herbicide treatments (kg ae/ha) included fluroxypyr at 0.31; a premix of dicamba plus diflufenzopyr at 0.14 plus 0.056, 0.21 plus 0.084, or 0.28 plus 0.11; fluroxypyr at 0.31 plus the premix of dicamba plus diflufenzopyr at 0.21 plus 0.084; dicamba (diglycolamine) at 2.2; dicamba at 1.1 and the premix of dicamba plus diflufenzopyr at 0.28 plus 0.11; glyphosate at 3.4; and fosamine at 6.0 alone or with imazapyr at 0.070. A methylated seed oil1/ was added to all treatments at 2.3 l/ha, except those containing fosamine, which included a non-ionic surfactant2/ at 0.25 percent, v/v. Visual ratings of percent initial cover by POLCU and percent POLCU injury were taken August 17 and September 23, 2005, 0 and 5 weeks after treatment (WAT), respectively. Percent POLCU cover and biomass reduction were evaluated July 24, 2006, 49 WAT. These data were subjected to analysis of variance, and means were compared using Fisher’s Protected LSD (p=0.05) (Table 1). At 5 WAT, percent injury ranged from 33 to 99 percent. Dicamba alone at 2.2 (kg ae/ha), or at 1.1 with the premix of dicamba plus diflufenzopyr at 0.28 plus 0.11; and glyphosate at 3.4 provided the greatest initial injury with values from 93 to 99 percent. At 49 WAT, the best-rated treatment was glyphosate at 3.4 (kg ae/ha), with percent POLCU cover and reduction ratings of 1 and 99 percent. Dicamba plus diflufenzopyr at 0.14 plus 0.056, or 0.21 plus 0.084 alone or in combination with fluroxypyr at 0.31 were the only treatments rated significantly different, with average POLCU cover values ranging from 44 to 70 percent, and percent POLCU reduction ranging from 57 to 67 percent. All other treatments averaged 4 to 38 percent POLCU cover and 80 to 96 percent POLCU reduction.

1/ 2/

Meth Oil, BASF, Research Triangle Park, NC Activator 90, Loveland Industries Inc., Greeley, CO.

74

93

Table 1. Japanese knotweed (Polygonum cuspidatum, POLCU) was mowed June 8, 2005, and treated with herbicides on August 17, 2005. Visual ratings of percent POLCU injury were taken September 23, 2005, 5 weeks after treatment (WAT). Percent POLCU cover and biomass reduction were evaluated July 24, 2006, 49 WAT. Each value is the mean of three replications. application POLCU injury POLCU cover POLCU reduction treatment rate 5 WAT 49 WAT 49 WAT kg ae/ha -------------------------- % ------------------------fluroxypyr

0.31

80

21

88

dicamba + diflufenzopyr

0.14 0.056

60

70

57

dicamba + diflufenzopyr

0.21 0.084

62

52

67

dicamba + diflufenzopyr

0.28 0.11

70

38

90

fluroxypyr dicamba + diflufenzopyr

0.31 0.21 0.084

83

44

63

dicamba

2.2

99

20

93

dicamba dicamba + diflufenzopyr

1.1 0.28 0.11

97

34

80

glyphosate

3.4

93

1

99

fosamine

6.0

33

11

95

67

4

96

15

39

28

fosamine 6.0 imazapyr 0.070 Protected LSD (p=0.05)

75

94

EVALUATION OF HERBICIDES FOR CONTROL OF AUTUMN OLIVE USING FOLIAR TREATMENTS. J.M. Johnson, A.E. Gover, and L.J. Kuhns, The Pennsylvania State Univ., University Park. ABSTRACT As part of an ongoing research project funded by the Pennsylvania Department of Transportation, a study was established to investigate the effectiveness of several herbicides and tank mixes for controlling autumn olive (Elaeagnus umbellata Thunb., ELGUM). This trial was established in a pasture near University Park, PA. Sixty ELGUM were tagged and measured to determine crown diameter and height. The treatment volume for each shrub was derived using the calculated crown profile area (average diameter by height) and a targeted application volume of 935 l/ha. Target plant height ranged from 1.7 to 3 m. The study was arranged in a randomized complete block design with twelve treatments and five replications, with each plant serving as a replicate. Treatments were foliar applied on July 7, 2005 using a CO2-powered sprayer equipped with a spray wand and single TeeJet XR8008VS tip. Herbicide treatments, in kg ae/ha, included metsulfuron at 0.042, alone or in combination with a premix of dicamba at 0.28 plus diflufenzopyr at 0.11; metsulfuron at 0.084 plus triclopyr (triethylamine) at 2.5; metsulfuron at 0.13 combined with either imazapyr at 0.56, fosamine at 12.1, picloram at 0.56, or fosamine at 12.1 plus imazapyr at 0.56; imazapyr at 1.1; glyphosate (isopropylamine) at 3.4; triclopyr at 3.4; and fosamine at 4.0 plus imazapyr at 0.07. A nonionic surfactant1 was added to all treatments at 0.25 percent v/v, except those containing the surfactant-loaded glyphosate. Percent canopy reduction was visually rated on September 1, 2005 and July 10, 2006, 8 and 50 weeks after treatment (WAT). At 8 WAT, ELGUM treated with triclopyr alone or in combination with metsulfuron was completely defoliated. ELGUM treated with metsulfuron plus fosamine and metsulfuron plus picloram was rated at 79 to 93 percent canopy reduction. When rated 50 WAT, ELGUM treated with metsulfuron at rates (kg ae/ha) of 0.084 or higher, imazapyr alone at 1.1, or triclopyr alone at 3.4 had average canopy reduction ratings of 91 to 100 percent. Reduction ratings for fosamine plus imazapyr were significantly lower than the best rated treatments at 70 percent. Treatments including metsulfuron at 0.042, or glyphosate alone at 3.4 were ineffective at controlling autumn olive.

1

ChemSurf 90, Chemorse Ltd., Des Moines, IA.

76

95

Table 1: Foliar herbicide treatments were applied to autumn olive (Elaeagnus umbellata, ELGUM) on July 7, 2005. Ratings were taken September 1, 2005 and July 10, 2006, 8 and 50 weeks after treatment (WAT). Each value is the mean of five replications. Four shrubs were not located during the rating conducted at 50 WAT. Means for the 50 WAT evaluation followed by the same letter are not significantly different according to Fisher's Protected LSD at p=0.05. application ELGUM canopy reduction treatment rate 8 WAT 50 WAT kg ae/ha -----------------%----------------untreated

---

0

0 e

metsulfuron

0.042

51

45 cd

metsulfuron dicamba + diflufenzopyr

0.042 0.28 0.11

35

23 de

metsulfuron triclopyr

0.084 2.5

100

100 a

metsulfuron imazapyr

0.13 0.56

51

98 a

metsulfuron fosamine

0.13 12.1

79

93 ab

metsulfuron picloram

0.13 0.56

93

91 ab

metsulfuron fosamine imazapyr

0.13 12.1 0.56

90

100 a

imazapyr

1.1

54

100 a

glyphosate

3.4

27

14 e

triclopyr

3.4

100

100 a

fosamine imazapyr Protected LSD (p=0.05)

4.0 0.07

32 26

77

70 bc ---

96

HOT WATER SYSTEMS FOR VEGETATION MANAGEMENT. R.G. Prostak and A.V. Barker, Univ. of Massachusetts, Amherst. ABSTRACT In recent years, the requests from the general public for non-chemical weed management strategies have increased. Two experiments were conducted at University of Massachusetts Crop Research and Education Center in Deerfield, MA to evaluate and compare two hot-water, weed-control systems. The AQUACIDE™ Environmental Weed Control System Model 665 by E.C.O. Systems Inc. delivers 5.6 gpm of super-heated hot water on demand at an operating temperature from 232 to 253 oF. Four types of wand-end applicators are available. The Waipuna Organic Hot Foam Weed Control System by Waipuna Systems Ltd of Auckland, New Zealand delivers 3.1 to 3.6 gpm of hot foam at an operating temperature from 203 to 208 oF. A plant sugar extract from corn and coconut is mixed with water at 0.4% v/v to produce the foam. Three types of wand-end applicators are available for the Waipuna. Both systems heat water with a number 2 oil burner. Experiment 1 was treated was treated on June 13, 2006. Four by twenty foot plots were treated with each machine at 1, 2, 3, or 4 minutes. Control of vegetation was assessed at 2, 17, 30, and 43 days after treatment (DAT). Experiment 2 was treated on July 11, 2006. Four by twenty foot plots were treated with each machine at 3, 3.5, 4.5, 5.25, 6, or 7 minutes. Control was assessed taken at 2, 15, 20, 35, and 52 DAT. The test site was a mixed stand of tall fescue (Festuca arundinacea Schreb.), quackgrass (Elytrigia repens Nevski), sweet vernalgrass (Anthoxanthum odoratum L.), orchardgrass (Dactylis glomerata L.), and timothy (Phleum pretense L.). The Aquacide and Waipuna machines provided similar levels of control at a given time interval treatment in each experiment. In experiment 1, Aquacide or Waipuna treatments at 2, 3, or 4 minutes resulted in mean control of 88% at 2 DAT, and the 1 minute treatment provided 69% control. At 43 DAT, mean control decreased to 10% at 1-minute time of treatment, 14% at 2 minutes, 24% at 3 minutes, and 42% at 4 minutes. In experiment 2, all treatments resulted in a mean of 98% control at 2 DAT and 80% control at 20 DAT. Percent control decreased to 41% at 35 DAT and 3% at 52 DAT. Control of vegetation by hot-water treatment lasts for about 5 weeks, and choice of implement may be based on convenience and costs of operation.

78

97

RAPID RESPONSE TO THE INVASIVE VINE, BUSHKILLER, IN NORTH CAROLINA. R.J. Richardson, A.M. West, and A.P. Gardner, North Carolina State Univ., Raleigh, NC. ABSTRACT Bushkiller (Cayratia japonica (Thunb.) Gagnep.) is an aggressive, perennial vine in the grape family (Vitaceae). Prior to 2005, this exotic species was only known to occur in North America in the Texas to Mississippi area. Bushkiller is somewhat similar in appearance to Virginia creeper (Parthenocissus quinquefolia (L.) Planch.). Both species bear leaves of five leaflets with serrated margins. However, bushkiller is herbaceous with a terminal leaflet larger than the other four leaflets providing a distinct appearance. Tendrils are opposite from leaves and do not have adhesive discs like Virginia creeper. The flowers are small yellow clusters and have not produced viable seed in North Carolina. In August 2005, an unknown weed sample was submitted to North Carolina State University for identification. This plant sample was soon recognized as bushkiller (Cayratia japonica (Thunb.) Gagnep.) and confirmed by herbaria samples. Local extension agents and homeowners were immediately contacted to arrange a site visit. By September, scientists from NCSU, APHIS, and USGS had visited the site in Winston-Salem, NC, to assess the situation. A small task force was then created to develop and execute an eradication plan. The task force obtained limited funding to begin eradication procedures in 2006. The plan consisted of foliar applications, cut-stem treatments, and handweeding of the infested site. Greenhouse trials indicated that triclopyr was the most efficacious herbicide on bushkiller with adequate selectivity for use on the infested site. NCSU personnel, county extension agents, and local volunteers participated in the eradication efforts with support of the affected homeowners. While vigor and density of the bushkiller population has been reduced, treatments will need to be continued at least through 2007 before complete eradication could be possible. Extension agents and the general public have not reported this species at any other sites in North Carolina.

79

98

SEEDHEAD SUPPRESSION OF ANNUAL BLUEGRASS ON A PUTTING GREEN IN 2006. M.B. Naedel and J.A. Borger, The Pennsylvania State Univ., University Park. ABSTRACT This study was conducted on a mixed stand of 'Pencross' creeping bentgrass (Agrostis stolonifera) and annual bluegrass (Poa annua) at the Penn State Blue Golf Course in State College, PA. The objective of the study was to evaluate selected growth regulators, with and without adjuvants, for the seedhead suppression of annual bluegrass. This study was a randomized complete block design with three replications, and a plot size of 21 ft2. Treatments were applied on April 6 (PRIOR), April 13 (BOOT), and May 6 (3 WAT), 2006, respectively, using a three-foot CO2 powered boom sprayer calibrated to deliver 40 gpa using one 11004E even tip/flat fan nozzle at 40 psi. Boot stage of the annual bluegrass was observed April 16, 2006. Non treated test areas within the test site revealed approximately 100% coverage of annual bluegrass seedheads. The site was maintained using cultural practices for irrigation, mowing, and fertilization that would be typical for a putting green. The test area was mowed twice with a Toro Triplex, bench set to 0.115", before the April 6, 2006 application of selected materials. During the study the site was fertilized with a Nature Safe 8-3-5 fertilizer at a rate of 1 lb N/1000 ft2 on May 1, 2006. Turfgrass phytotoxicity was rated five times during the study. The turfgrass phytotoxicity was variable and in some cases lasted for several weeks. On the first rating date, April 24, 2005, turfgrass treated with Embark at 40 oz/A, Embark at 40 oz/A plus MacroSorb Foliar at any rate, Embark at 20 oz/A plus Primo and Proxy applies twice, Embark at 40 oz/A plus ECO-N, Proxy plus Primo plus Trimmit with or without ECO-N (BOOT), any combination of Trimmit and Embark, and Primo (PRIOR) plus Embark at 40 oz/A (BOOT) plus Ferromec (BOOT) was rated less than acceptable for phytotoxicity 7.0. Annual bluegrass seedhead suppression was rated three times during the study. On the last rating date, May 26, 2006, turfgrass treated with Embark at 40 oz/A with and without Ferromec, Embark at 40 oz/A plus MacroSorb Foliar at 8 oz/1000 ft2, Embark at 40 oz/A plus MacroSorb Foliar at 4 oz/1000 ft2, plus Ferromec, Proxy plus Primo plus ECO-N (BOOT/3 WAT), Embark at 20 oz/A (BOOT) plus Primo plus Proxy (BOOT/3 WAT), Embark at 40 oz/A plus ECO-N, Proxy plus Primo plus Trimmit plus ECO-N, Primo plus Trimmit plus Embark at 40 oz/A with and without ECO-N, Trimmit plus Embark at 40 oz/A with and without ECO-N, Proxy (PRIOR) plus Embark at 40 oz/A plus Ferromec (BOOT), Primo (PRIOR) plus Embark at 40 oz/A plus Ferromec (BOOT), ECO-N (PRIOR) plus Embark at 40 oz/A plus Ferromec (BOOT), and Embark at 40 oz/A plus Signature plus Ferromec had significantly fewer annual bluegrass seedheads than untreated turfgrass and had at least 75% reduction of the seedheads.

80

99

THE EFFECTS OF FERTILIZER ON THE TOLERANCE OF KENTUCKY BLUEGRASS TO BISPYRIBAC-SODIUM HERBICIDE. R.R. Shortell, S.A. Bonos, and S.E. Hart, Rutgers Univ., New Brunswick, NJ. ABSTRACT Kentucky bluegrass (Poa pratensis L.) is a diverse grass species used for turf that has been shown to exhibit a variable response to bispyribac-sodium herbicide, which is commonly used in other cool season turfgrasses for grassy weed control. The objective of this study was to evaluate the effects of nitrogen fertility on the tolerance of Kentucky bluegrass to this herbicide. Two trials were seeded in 2004 and 2005, respectively, at the Rutgers University Plant Science Research Center in Adelphia, NJ. Six cultivars were chosen as exemplars to represent the full range of response to this herbicide. 'Avalanche' and ‘Washington’ were used to represent the susceptible grouping with injury in excess of 80 percent, ‘Midnight’ and ‘Boutique’ were used to represent the moderate grouping with injury of 34 and 38 percent, respectively, and ‘Lakeshore’ and ‘SR 2284’ were chosen for their tolerance to this herbicide showing less then 25 percent injury. Nitrogen treatments were broken into plus or minus one pound nitrogen per 1,000 ft2 using a homogenous 16-4-8 formulation, applied 4 days before initial herbicide applications. Bispyribac-sodium was applied at two rates (30 g a.i./A followed by 30 g a.i./A, and 60 g a.i./A followed by 60 g a.i./A) using a sequential application spaced 21 days apart in late June. Percent turfgrass injury was rated on a weekly basis and percent ground cover was noted at the completion of the study. Based on the results of this study it appears that the injury of tolerant cultivars is masked by the nitrogen application, injury in moderate cultivars is not significantly affected by the nitrogen application, and injury in the susceptible cultivars is actually increased by the application of nitrogen. The potential exists to safely use bispyribacsodium herbicide on some Kentucky bluegrass cultivars; however future research to determine the mechanisms of this response is warranted.

81

100

ROUGHSTALK BLUEGRASS CONTROL WITH BISPYRIBAC-SODIUM AND SULFOSULFURON. P. McCullough and S. Hart, Rutgers Univ., New Brunswick, NJ. ABSTRACT Bispyribac-sodium and sulfosulfuron are new ALS-inhibiting herbicides registered for use in creeping bentgrass fairways for selective roughstalk bluegrass control but limited comprehensive investigations have been conducted to evaluate efficacy for longterm management. Field experiments were conducted from June 2005 to October 2006 (Study 1) and from June 2006 to October 2006 (Study 2) on a fairway at New Jersey National Golf Club in Basking Ridge, NJ. Bispyribac-sodium was applied twice at 37, 74, or 111 g a.i./ha or thrice at 37 or 74 g/ha. Sulfosulfuron was applied twice or thrice at 6.5, 13, or 26 g a.i./ha or once at 26 g/ha. Initial applications were made June 10, 2005 and June 1, 2006 and sequential applications were made at three week intervals. Applications were made at 220 l/ha and a non-ionic surfactant was included at 0.25% v/v for sulfosulfuron treatments. Creeping bentgrass chlorosis from herbicides was acceptable (< 20%) by 2 to 3 weeks after applications while all treatments provided substantial reductions in roughstalk bluegrass cover (>90%) by late July. However, roughstalk bluegrass had regrown by October in both years suggesting herbicide applications visually eliminated foliage but did not control vegetative reproductive structures. Since roughstalk bluegrass has a wide genetic diversity, further investigations are needed to determine if these results are correlated with biotype tolerance to herbicide applications or from ineffective herbicide translocation. Overall, bispyribac-sodium and sulfosulfuron effectively eliminated roughstalk bluegrass ground cover in summer months but regrowth during fall months prevented successful longterm control.

82

101

CRITICAL WEED-FREE PERIOD FOR OVERSEEDED BERMUDAGRASS IN NORTHERN CLIMATES. B.W. Compton and S.D. Askew, Virginia Tech, Blacksburg. ABSTRACT In the transition zone, it is common to overseed warm season bermudagrass (BG) (Cynodon dactylon) with cool season perennial ryegrass (PRG) (Lolium perenne) to improve winter aesthetics on golf courses. Most golf revenue is generated during spring and early summer due to ideal weather conditions. PRG is needed to provide desirable quality and playing conditions for fairway turf but competitively injures BG during this period. BG has the ability to recover from PRG competition given enough time during the summer. It has been suggested that healthy BG needs 100 days of weed-free growth in summer, yet research has not been conducted to validate or test this claim. “Healthy” BG is a subjective term that is usually based on biomass accumulation, total nonstructural carbohydrate (TNC), and ability of plants to survive stresses such as cold, heat, or UV light. Our objective is to measure how duration of PRG competition influences BG health. Studies were conducted in Blacksburg, VA on Patriot BG at VA Tech’s Glade Road Research Facility and on Midiron BG at the Turfgrass Research Center. Foramsulfuron (Revolver) at 17 oz/A, was applied at weekly intervals for 24 weeks between April 4 and August 29, 2006. To assess BG “health”, BG and PRG cover was visually evaluated on September 29 and 80cm2 plugs of turf were collected from each plot on October 15 to assess dry biomass, TNC, and electrolyte leakage (following cold stress). Electrolyte leakage and TNC data are still being collected and will be discussed later. Data were subjected to analysis of variance using a repeated measures technique and regressions were used to describe effects of BG weed-free period on measured responses. Green shoots were evident on Patriot and Midiron BG on March 25 and April 6, respectively, and both cultivars stopped growing at first frost on October 1. Therefore, the greatest possible growing season was 178 to 190 days, depending on cultivar. However, growing degree days at base 65 (GDD65), the typical growth model for BG, were only accumulated between May 26 and September 24, a period of 121 days. PRG left to compete with BG beyond July 25 (less than 68 weed-free days) reduced BG visual cover 10 to 20% and 13 to 35% in Patriot and Midiron BG, respectively. As the duration of weed-free growth increased, BG above-ground dry biomass increased from 777 to 1322g/m2 for Patriot and 350 to 525g/m2 for Midiron. Patriot dry biomass increased linearly at a rate of 3g/m2 for each additional day of weed-free growth while Midiron biomass exhibited a hyperbolic response with an asymptote at approximately 89 days. This differential biomass accumulation indicates that Patriot continues to compete with ryegrass and grow during the entire season while Midiron does not. Thus, Midiron has a higher requirement for weed free period than Patriot. The 89-day asymptote for Midiron biomass accumulation represents 309 GDD65 out of a total of 621 GDD65 for the entire season. Although the TNC and electrolyte leakage data yet to be collected represent the most important indicators of BG health, we can tentatively conclude that 100 days of growth is a safe assumption for less competitive cultivars like Midiron but may be overly conservative for cultivars like Patriot.

83

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EFFECT OF DEW AND GRANULAR FORMULATION ON MESOTRIONE EFFICACY FOR LAWN WEED CONTROL. M.J. Goddard, S.D. Askew, J.B. Willis, Virginia Tech, Blacksburg, R.J. Keese, Syngenta Crop Protection, Carmel, IN, and J.R. James, Syngenta Crop Protection, Greensboro, NC. ABSTRACT Lawn weed control is typically achieved with granular herbicides. Scotts™ Turf Builder™ Plus 2™ (28-3-3 fertilizer plus 1.21% 2, 4-D, and 0.605% MCPP), the most common granular herbicide for lawns, requires dew on leaf foliage for best results. With dew present, granules stick to leaves instead of falling through the turf canopy. Granular formulations of mesotrione are being developed for both consumer and professional markets. Since mesotrione is absorbed though both foliage and roots, it may be less dependent on dew than industry standards for consumer markets. Studies were conducted at two sites in Blacksburg, VA to evaluate granular combination products of mesotrione and fertilizer, compared to 2,4-D plus MCPP for consumer lawn care. Our objective was to determine the effects of granular formulation and dew on efficacy of mesotrione and 2,4-D plus MCPP for control of common lawn weeds. We evaluated three mesotrione granular products including a 29-3-4 fertilizer similar to Scotts™ Turfbuilder™ that contains mesotrione at 0.2% (EXC853), the same fertilizer with mesotrione at 0.2% and prodiamine at 0.4% (EXC856), and a 29-3-4 fertilizer similar to Vigaro™ that contains mesotrione at 0.25% (EXC950). These mesotrione products were compared to a commercial 28-3-3 fertilizer with 1.21% 2,4-D and 0.61% MCPP (Scotts™ Turfbuilder™ Plus 2™). All products were applied at 140 kg/ha. The study areas consisted of Kentucky bluegrass (Poa pratensis) containing dandelion (Taraxacum officinale), corn speedwell (CSP) (Veronica arvensis), and white clover (Trifolium repens). The four granular herbicides were applied in early AM while foliage was still wet with natural dew and in the afternoon of the same day to dry turf. All treatments received 0.4 cm irrigation within 48 h. The presence of dew did not influence dandelion and white clover control by mesotrione while dew increased CSP control by mesotrione with one of the three granular products. Mesotrione on the fertilizer carrier similar to Vigaro™ did not control dandelion, CSP or white clover as well as mesotrione on the fertilizer carrier similar to Scotts™. For example, Mesotrione controlled dandelion 90, 86, and 58% and white clover 90, 87, and 67% as EXC 856, EXC 853, and EXC 950, respectively 28 days after treatment (DAT) regardless of dew presence. In contrast, 2,4-D + MCPP controlled dandelion and white clover 88% when applied to wet foliage and 33 and 18%, respectively, when applied to dry foliage. EXC 856 controlled CSP 88%, regardless of dew while EXC 853 controlled CSP equivalently when dew was present but less (65%) when leaves were dry. In contrast, EXC 950 controlled CSP 43% when dew was present and more (58%) when leaves were dry. 2,4-D plus MCPP did not control CSP, regardless of dew. In this study, mesotrione controlled weeds equivalent or superior to the commercial standard and could be a viable product for consumer markets.

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ABSORPTION, TRANSLOCATION, AND METABOLISM OF FORAMSULFURON IN DALLISGRASS. G.M. Henry, J.D. Burton, and F.H. Yelverton, North Carolina State Univ., Raleigh. ABSTRACT Dallisgrass (Paspalum dilatatum Poir.) is a rhizomatous perennial warm-season grass that commonly infests managed turfgrass systems. The sulfonylurea herbicide foramsulfuron was recently registered (2003) for use in turfgrass for the postemergence control of several cool-season grasses, goosegrass, and henbit present within warmseason turf. Preliminary analysis of this herbicide has shown it to be a potential alternative to MSMA and glyphosate for the control of dallisgrass. Previous research was conducted to determine the efficacy of foramsulfuron applied alone or in combination with MSMA at various rates and timings. Foramsulfuron applied alone only provided < 5% control of dallisgrass 1 year after initial treatment (YAIT), while treatments containing the application of MSMA followed by foramsulfuron provided > 30% control 1 YAIT. Therefore, the objective of our research was to examine the effect of pre applications of MSMA on the absorption, translocation, and metabolism of 14Cforamsulfuron when foliar applied to mature dallisgrass. Naturally occurring populations of dallisgrass were obtained locally and propagated in the greenhouse. Foliar absorption of 14C-foramsulfuron was measured during a 48-h period. Herbicide treatments were prepared using 2-pyrimidyl 14C-foramsulfuron (4.51 MBq mg−1 specific activity, 98% purity). Treatments consisted of foramsulfuron (0.075 kg/ha) followed by followed by foramsulfuron 2 weeks after initial treatment (WAIT), MSMA (1.25 kg/ha) followed by foramsulfuron 2 WAIT, and no pre-treatment followed by foramsulfuron 2 WAIT. Radiolabeled material was applied during the second application of each treatment. Mature dallisgrass plants (20 cm in height) were selected to receive 14Cforamsulfuron treatments. Herbicide absorption was quantified at 0, 2, 4, 8, 24, and 48 h after treatment. At the appropriate harvest interval, the treated leaf was excised and rinsed in 50:50 methanol–water solution to remove unabsorbed 14C. After the methanol wash, the treated leaf was frozen. Each methanol leaf wash vial received 10 ml scintillation cocktail. Treated leaves were combusted in a biological sample oxidizer using a mixture of carbon dioxide absorbent and scintillation fluid to trap evolved 14CO2. All samples were then quantified by liquid scintillation spectroscopy. Data from this experiment are currently being analyzed.

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USE OF TRICLOPYR TO REDUCE ANTICHROMATIC EFFECTS OF MESOTRIONE IN TURFGRASS. J.B. Willis and S.D. Askew, Virginia Tech, Blacksburg. ABSTRACT Chromatic is defined as all colors other than white, black, and pure gray. When phydroxyphenylpyruvate dioxygenase inhibitors (HPPD) are applied to susceptible plants, leaves turn white. This response can be described as antichromatic. Mesotrione is an HPPD inhibitor that is currently being evaluated for use in turfgrass. Many turfgrass managers have indicated that their clientele will be unpleased with discoloration caused by mesotrione. Previous research at Virginia Tech evaluated all combinations of mesotrione, triclopyr, and fenoxaprop-P for common bermudagrass control. An interesting result was that plots treated with combinations of mesotrione and triclopyr had higher turf color than plots treated with mesotrione alone. Therefore, we speculate that triclopyr is an effective tank-mix partner for reducing antichromatic effects of mesotrione and improving efficacy towards perennial broadleaf weeds. Our objective is to evaluate mesotrione plus triclopyr for effects on turfgrass and weed color and control. Studies were conducted at two low-maintenance lawn locations and used a 2 by 4 factorial treatment arrangement. The first factor was single or sequential treatment and the second factor was the following herbicide treatment combinations: mesotrione at 0.125 lb ai/A, triclopyr at 1 lb ai/A, mesotrione + triclopyr, and an industry standard for broadleaf weeds, SpeedZone® at 4 pt/A. Fenoxaprop-P at 0.12 lb ai/A applied twice and a nontreated check were included as comparison treatments. Sequential applications were made at 3-wk intervals. Turf color was visually estimated (9 = ideal green; 1 = no green) based on an assessment of both desirable turfgrass and weeds. Tank-mixing mesotrione and triclopyr improves turf color compared to mesotrione alone. Turf color was reduced by mesotrione alone mostly due to whitened nimblewill (NW) and white clover, the predominant weed species accounting for 40-60% of initial ground cover. Results from previous research with mesotrione indicate that single applications do not effectively control NW, and adding triclopyr in the current trial did not improve NW control with single applications. However, triclopyr does not decrease NW control by mesotrione although it greatly increase turf color by eliminating antichromatic effects of mesotrione on NW. NW control 60 DAT was equivalent between sequential applications of mesotrione alone and mesotrione plus triclopyr and averaged 65% at one location and 78% at another location while no other treatment controlled NW. Sequential applications of mesotrione and single applications of triclopyr effectively control ground ivy. Tank mixing mesotrione and triclopyr with one application improved ground ivy control to 97% compared to 0 and 70% control by single applications of mesotrione and triclopyr, respectively with similar effects on broadleaf plantain. PowerZone® controlled broadleaf plantain and not ground ivy. Mesotrione controlled white clover only when mixed with triclopyr. The combination of mesotrione and triclopyr both reduces the antichromatic response of susceptible species and adds control of perennial broadleaf weeds that mesotrione alone does not control. Ongoing research is evaluating mesotrione plus triclopyr compared to each product alone for injury to Kentucky bluegrass, perennial ryegrass, bermudagrass, tall fescue, and fine fescue.

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METHODS TO ASSESS ENVIRONMENTAL INFLUENCE ON TURFGRASS RESPONSE TO MESOTRIONE. S.D. Askew, M.J. Goddard and J.B. Willis, Virginia Tech, Blacksburg. Mesotrione is expected to be available for turfgrass markets Spring 2008. Of several turfgrass species known to tolerate mesotrione treatment, perennial ryegrass (PRG)(Lolium perenne) and fine fescue (Festuca spp.) are among the most sensitive. The visual manifestation of turfgrass injury from mesotrione is striking and ranges from a dull yellow to bright white. It is hard to predict when turfgrass will be discolored by mesotrione. In several field trials since 2001, we have observed turfgrass responses to mesotrione 4 SC at 0.14 to 0.28 kg ai/ha range from no effect to completely white foliage. Studies were conducted in 2006 at three field locations and in growth chambers in Blacksburg, VA to evaluate the influence of various environmental conditions on PRG and hard fescue (Festuca longifolia) response to mesotrione. In growth chamber studies, mesotrione was applied at 0, 0.14, 0.21, and 0.28 kg ai/ha to PRG maintained at daytime and nighttime temperatures of 13 and 7, 18 and 13, 24 and 18, and 30 and 24 C, respectively. PRG was placed in 15 cm x 15 cm pots and maintained at 2.5 cm in height. Chlorophyll b and a + b levels decreased by 750 µg g-1 fresh weight and 2970 µg g-1 fresh weight, respectively, for each 100g increase in herbicide rate. Carotenoid levels were strongly temperature dependent and followed a quadratic response with peak carotenoid production (820 µg g-1 fresh weight) occurring near 25 C, the plants growth optimum. In field trials, weather stations (Spectrum Technologies) were installed at each site to monitor soil moisture, soil temperature, air temperature, dew period, solar radiation, and photosynthetically active radiation every 30 minutes. Mesotrione was applied at 0.14 kg ai/ha each week between March 8, 2006 and September 4, 2006. A sample of leaf tissue was collected just prior to treatments, 5 days after treatment (DAT) and 10 DAT. At each evaluation timing, leaf tissue was assayed for cuticle wax weight, carotenoids, and chlorophyll a and b. Plots were also evaluated for color both visually and with digital image analysis. Principle component analysis (PCA) techniques and regressions were used to determine correlations between measured environmental conditions and observed treatment responses. The PCA analysis indicates some correlation between carotenoids and several environmental conditions. However, correlation between visual injury responses due to mesotrione and environmental conditions will likely be complicated. As with other carotenoid synthesis inhibitors, the greatest amount of white tissue occurs during maximum plant growth, as white tissue is typically evident on new leaves. Several factors, however, can influence plant growth including a combination of abiotic factors or even biotic factors such as disease. Thus, turfgrass injury response will be difficult to predict based on environmental conditions before and after treatment. Turfgrass growth rate will likely be the best predictor of injury responses, with increase growth resulting in increased chances for white foliage. Preliminary studies also indicate that conditions that promote foliar absorption of mesotrione, such as high humidity, will also contribute to turfgrass injury. Our future work will evaluate absorption as a contributing factor.

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YELLOW NUTSEDGE CONTROL WITH SULFENTRAZONE, SULFOSULFURON AND MESOTRIONE. P.H. Dernoeden, J. Fu, and S.J. McDonald, Univ. Maryland, College Park. ABSTRACT Yellow nutsedge (Cyperus esculentus, CYPES) is a common problematic weed in turfgrasses. Three field studies were conducted in 2005 and 2006. Study I involved a single application of six rates of sulfosulfuron (0.012, 0.024, 0.036, 0.047, 0.059 and 0.070 lb ai/A) and halosulfuron (0.06 lb ai/A) on 17 August 2005. Study II was a preemergence study in which mesotrione was applied once or sequentially (0.25 and 0.125 + 0.125 lb ai/A) and sulfosulfuron (0.05 lb ai/A) was applied only once beginning on 21 April 2006. Study III compared the effectiveness of single and sequential postemergence applications of sulfentrazone (0.125, 0.250, 0.375 and 0.125 + 0.125, 0.250 + 0.250, 0.375 + 0.375 lb ai/A); mesotrione (0.250 and 0.125 + 0.125 lb ai/A); and sulfosulfuron (0.05 lb ai/A) beginning on 26 May and the sequential treatments were applied 16 June 2006. In Studies I and III, plots were 5 ft by 5 ft and were arranged in a randomized complete block with four replications. In Study II, plots were 5 ft by 10 ft with two replicates. Herbicides were applied in 50 GPA using a CO2 pressurized (35 psi) sprayer equipped with an 8004E flat fan nozzle. Postemergence treatments were applied to 2.5-3.0 inch tall CYPES plants. Injury and weed cover data were subjected to analyses of variance and significantly different means were separated using Fisher’s least significant difference test at P ≤ 0.05. Mesotrione and sulfosulfuron, but not sulfentrazone, were tank-mixed with a non-ionic surfactant at 0.25% v/v. In Study I, sulfosulfuron treatments were applied 17 August and all treatments provided an equal level of burndown or browning of CYPES leaves by 13 Sep. 2005. Numerous plants treated at the lower two rates had some green leaf tissue and may have recovered. The plots were not monitored thereafter and potential recovery of CYPES plants from tubers was not determined. In Study II and III, the site was treated with glyphosate in early April and diskseeded with perennial ryegrass (Lolium perenne) on 19 April 2006. In Study II, treatments were applied preemergence on 21 April and the sequential mesotrione treatment was applied 18 May 2006. CYPES began to emerge from tubers on 24 April. Mesotrione did not affect perennial ryegrass emergence or vigor, but sulfosulfuron reduced germination and seedlings vigor in May. Perennial ryegrass cover, however, was equal among herbicide-treated plots by 13 July (78 to 88%), which was statistically greater than was observed in untreated plots (55%). Sulfosulfuron and mesotrionetreated plots (0.25 lb ai/A) had 11 to 16% CYPES cover, while mesotrione (0.125 + 0.125 lb ai/A)-treated plots had 2% CYPES cover on 13 July. Plots were evaluated for CYPES recovery from tubers on 15 September. CYPES in sulfosulfuron-treated plots had recovered (34% CYPES cover) and levels were statistically equivalent to untreated plots (45% CYPES cover). Mesotrione (0.125 + 0.125 lb ai/A)-treated plots had only 4% CYPES cover on 15 Sep. In Study III, sulfentrazone (0.375 lb ai/A, and all sequentials) had provided excellent CYPES control (0 to1% CYPES cover); mesotrione provided fair control (8 to 13% CYPES cover), and sulfosulfuron (39% CYPES cover) provided no control, when compared to untreated plots (32% CYPES cover) on 15 Sep. 2006.

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PRELIMINARY STUDY AT FOUR LOCATIONS ON USING GROWING DEGREE-DAYS TO APPLY A PREMERGENCE HERBICIDE. M.A. Fidanza, The Pennsylvania State Univ., Reading, J.A. Borger and M.B. Naedel, The Pennsylvania State Univ., University Park, C.A. Bigelow, Purdue Univ., West Lafayette, IN, and P.C. Bhowmik, Univ. of Massachusetts, Amherst. ABSTRACT Crabgrass (Digitaria spp.) is a troublesome and problematic annual grass weed in cultured turfgrass. Preemergence herbicides are often used for the control of crabgrass in lawns, however, in some years the level of control is considered marginal or not commercially acceptable. The issue of poor or unacceptable crabgrass control from preemergence herbicides in lawns may involve the early-to-mid spring application timing of these kinds of products. Therefore, the objective of this research was to attempt to determine optimum application timing for a commonly used preemergence herbicide for the control of crabgrass in cool-season turfgrass maintained as a lawn. The same field study was conducted during March through September, 2006, on a mixed stand of cool-season turfgrass at four locations: (1) Bellewood Golf Course, North Coventry, PA, (2) Pennsylvania State University, University Park, PA, (3) Purdue University, West Lafayette, IN, and (4) University of Massachusetts, Amherst, MA. The preemergence herbicide prodiamine (trade name = Barricade 65WG) was applied at 0.55 kg ai/ha (0.75 lbs product/A) over a range of 15 different cumulative growing degree-day accumulations, as follows: 0 - 10, 11 – 20, 21 – 30, 31 – 40, 41 – 50, 51 – 60, 61 – 70, 71 – 80, 81 – 90, 91 – 100, 101 – 120, 121 – 140, 141 – 160, 161 – 180, and 181 – 200. A base temperature of 10 C (50 °F) was used to calculate cumulative degree-days from soil temperatures derived from each location via satellite weather data. An untreated check was also included in the treatments, which were arranged in a randomized complete block design with three or four replications depending on the study location. Also, individual plot size varied according to study location, and mowing height ranged from 5.0 to 7.5 cm (2 to 3 inches). At each location, the treatments were applied from flat-fan nozzles with a CO2-powered backpack sprayer through an average of about 408 gal water carrier per ha (1 gal water per 1000 sq ft) at 250 kPa (35 psi). Preliminary analysis revealed that crabgrass control varied among the application timings at all four locations. Also, preliminary analysis of the data from all four locations indicated a need for improved accuracy with accessing soil temperature-based cumulative growing degree-day information.

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PRE AND POST EMERGENT ANNUAL BLUEGRASS CONTROL. J.A. Borger, M.B. Naedel, M.D. Soika and T.L. Watschke, The Pennsylvania State Univ., University Park. ABSTRACT This study was conducted on a mature stand of 'Penneagle' creeping bentgrass (Agrostis stolonifera) and annual bluegrass (Poa annua) at the Valentine Turfgrass Research Center, Penn State University, University Park. The objective of the study was to determine if selected materials could reduce the annual bluegrass population under simulated fairway conditions. This study was a randomized complete block design with three replications. Treatments were applied on several dates using a three foot CO2 powered boom sprayer calibrated to deliver 40 gpa and Betasan was applied at 80 gpa using two, flat fan, 11004 nozzles at 40 psi. The test area was maintained to simulate a golf course fairway. The test site consisted of approximately 45 percent creeping bentgrass and 55 percent annual bluegrass at the initiation of the study. Turfgrass discoloration was rated five times during the study. Only turfgrass treated with Velocity, alone or in combination with other materials, was rated below acceptable (7.0) at some time in the study. Turfgrass quality was rated five times during the study. Turfgrass quality was never rated below acceptable (7.0) on any rating date. Turfgrass spring color was rated twice during the study. On the April 13, 2006 rating date only turfgrass treated with Prograss, alone or in combination with other materials, was rated below 6.0. By the May 9, 2006 rating date, all turfgrass spring color was rated 9.0. The annual bluegrass population change was rated on May 9, 2006. Turfgrass treated with Trimmit plus Rubigan at 0.75 oz/1,000 ft2 with or without an 18-3-1 fertilizer applied at the June, 28, 56, 112, and 140 DAT timings, Trimmit plus Rubigan at 1.5 oz/1,000 ft2 applied at the June, 28, 56, 112, and 140 DAT timings, Velocity at 60 g ai/A June and 14 DAT plus Rubigan at 0.75 oz/1,000 ft2 June 14, 42, 70, and 98 DAT, Trimmit with or without Rubigan at 0.75 oz/M plus an 18-3-1 fertilizer applied at the June, 28, 56, 112, and 140 DAT timings with or without Betasan at 5.6 oz/1,000 ft2 applied at June, and 56 DAT timings, Trimmit plus Signature at 8 oz/1,000 ft2 plus an 18-3-1 fertilizer applied at the June, 28, 56, 112, and 140 DAT timings with or without Betasan at 5.6 oz/1,000 ft2 applied at June, and 56 DAT timings, Trimmit applied at the June, 28, 56, 112, and 140 DAT timings plus Rubigan at 0.75 oz/1,000 ft2 applied at the June, 14, 28, 42, 56, 70, 84, 98, 112, and 140 DAT timings, Prograss alone or in combination with Trimmit at any rate, and Trimmit plus Signature applied at the June, 28, 56, 112, and 140 DAT timings reduced the annual bluegrass population by 70% or more, significantly more reduction than untreated. It appears that annual bluegrass populations can be reduced in a mixed sward of creeping bentgrass/annual bluegrass using Trimmit, Velocity, and Prograss alone or in combination with a fertilizer, fungicides, and a preemergence.

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APPLICATOR EXPOSURE AND DRIFT OF LAWN CHEMICALS WITH A WET BLADE MOWER AND THREE FOLIAR SPRAY METHODS. S.D. Askew, Virginia Tech, Blacksburg. ABSTRACT In the home lawn environment, applicators, residents, and surrounding vegetation are all at risk of pesticide exposure. Herbicides such as 2,4-D have been shown to dislodge from treated lawns and be deposited inside the home on various surfaces. Thus, limiting applicator exposure, reentry exposure, and drift are all valuable attributes to any application method. The wet blade mower delivers chemicals and nutrients to plants by wiping liquid product onto the cut plant surface. This liquid delivery method has several potential benefits compared to conventional spray techniques. Our objective was to evaluate applicator exposure, reentry exposure, and drift of liquids applied with the wet blade mower (WB), a rear-mounted boom-type sprayer (BS), a backpack sprayer with hand wand (BP), and a commercial “spray gun” type sprayer (SG). A spray pattern indicator, Brazon (1% solution), was used in this study. Mixed tall fescue and Kentucky bluegrass turf maintained at 2.5 inch were divided into 500 ft2 plots. These plots were treated with 2.5 gal of Brazon/A at a delivery rate of 43.6 gal/A for foliar spray methods and 2.5 gal/A for the WB. Filter papers were placed at regular intervals leading away from the sprayer’s first pass in each plot. A wind source was positioned to supply a sustained wind speed of 5 to 7 mph. The first pass of the applicator was upwind of the evenly spaced filter papers; papers were immediately collected after the applicator passed. Filter papers were affixed to the applicator’s spray suit to test exposure at different areas on the body. These papers were collected after each treated plot and analyzed. In addition, papers were affixed to the bottom, front, and top of the right shoe and plots were traversed twice at 10 min and 24 hr after treatment. Each of the four application methods were replicated three times in a RCB and the study was conducted on October 27, 2005, October 3 and 4, 2006 at three different sites. Substantial drift occurred from all foliar spray application methods but not from the WB. When actual dye values were converted, the foliar spray application methods deposited 77 to 86% of a full rate on bare ground while the WB deposited 22% of a full rate to bare ground. Thus, the WB does not apply as much chemical to areas that are void of vegetation. The small amount of chemical deposited by the mower is attributed to “shatter” effect as the wet undersurface of the mower blade contacts grass leaf blades at high velocity and propels small droplets onto neighboring areas under the mower deck. As much as 58 to 81% of a full application rate was extracted from the shoe front 10 min after treatment with foliar spray methods and 35% was extracted 10 min after WB application. After 24 hr, all application methods resulted in 2 to 7% of the full rate dislodged by filter paper and were statistically equivalent. WB and rear boom application methods did not expose the applicator to any chemical while SG and pump sprayer methods exposed the worker to between 6.1 and 8.9 μl of dye. In some locations on the body (e.g., shoes), the applicator was exposed to nearly a full chemical rate. The WB method reduced drift, applicator and early reentry exposure to chemical dye in all studies.

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PUMPKIN RESPONSE TO HALOSUFSULFURON, FOMESAFEN, AND TERBACIL. R.B. Batts, North Caroline State Univ., Raleigh, A.W. MacRae, University of Georgia, Tifton, and J.B. Beam, North Carolina Cooperative Ext. Service, Lincolnton. ABSTRACT Pumpkin trials were conducted in Iron Station and Edenton, NC and Blairsville, GA in 2006 to determine crop tolerance and yield response of ‘Magic Lantern’ and ‘Appalachian’ pumpkin to halosulfuron (Sandea 75 DF), fomesafen (Reflex 2 SC) and terbacil (Sinbar 80 WP). Sandea was applied preemergence (PRE), postemergence (POST) or post-directed (P-DIR) at 0.5, 0.75, or 1.0 oz/A. Reflex and Sinbar was applied PRE at 1 or 2 pt/A and 3 or 6 oz/A, respectively. For comparison purposes, a hand-weeded control was included. Injury data were combined across cultivars at all locations and across both North Carolina sites. Compared to the hand-weeded control, Sandea applied PRE, POST, and P-DIR injured pumpkin 37-51, 33-37, and 18-20%, respectively, in North Carolina 2 wks after treatment (WAT). In contrast, injury seen in Georgia ranged from 5-7%, 1932%, and 0% when applied PRE, POST, and P-DIR, respectively. Optimum growing conditions were prevalent in Georgia for the duration of the growing season, limiting injury from herbicide application. Similar results were observed with Reflex and Sinbar applications in North Carolina causing 26-56 and 84-98% injury, respectively, while in Georgia these applications only caused 4-13 and 16-65% injury. Severe injury from Sinbar applications resulted in a reduction in pumpkin stand. Sandea P-DIR had the least amount of injury at all locations, while the PRE timing was most injurious in North Carolina and POST was most injurious in Georgia. PRE injury was expressed as crop stunting, while POST and P-DIR injury appeared as discoloration in the terminals of the plants. As with injury, yield data were combined across cultivar at all sites and across both North Carolina locations. When compared to the hand-weeded control in North Carolina, yield reduction (total weight) from Sandea treatments ranged from 10 to 25% with no trend for rate or timing of application. Yield reduction from the high rate of Reflex and both rates of Sinbar were greater than any other treatment in North Carolina. Similarly, these three were the only treatments to have greater plant stand reduction compared to the nontreated control. In Georgia, the two Sinbar treatments were the only treatments with reduction in yield compared to the nontreated control. The only reduction in plant stand was with the high rate of Sinbar. Based on these data, Sandea appears to be relatively safe to pumpkins, especially in heavy weed situations where some injury is acceptable. However, Sinbar appears to be too injurious, especially if heavy or excessive rainfall follows a PRE application.

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ASSESSMENT OF THE COMBINED EFFECTS OF MESOTRIONE AND HEXAZINONE ON WEEDS IN WILD MAINE BLUEBERRIES. D.E. Yarborough and K.F.L. Guiseppe, University of Maine, Orono. ABSTRACT Hexazinone has been the principle herbicide used in Maine wild blueberry (Vaccinium angustifolium) fields for over twenty years. There is evidence that reliance on hexazinone without other alternative herbicides has resulted in increased populations of grasses and other herbaceous weeds. There is a need for herbicides with different modes of action for herbicide rotations in wild blueberry fields. In order to evaluate the herbicide mesotrione with and without hexazinone a split block design was established on six wild blueberry fields throughout the state to obtain a diversity of soil types and weed species. A block was established in the Maine towns of Union, Belfast, Penobscot, Orland, Township 19 and at the Blueberry Hill Experimental Farm in Jonesboro. A 16 x 20 m block was comprised of 4 x 16 m treatment plots including an untreated control, mesotrione at 444 ml/ha preemergence, 222 ml/ha preemergence and 222 ml/ha postemergence on the same plot, and 222 ml/ha postemergence. At right angles on an 8 x 20 m plot of either an untreated control or a hexazinone treatment at 1 kg/ha was applied to give a total of eight combinations. Pre-emergence treatments were sprayed on 8-11 May. Postemergence treatments were sprayed on 6-9 June. Treatment effects were assessed for broadleaf, fern and grass weed cover using a Daubenmire cover scale and wild blueberry phytotoxicity as percent injury from four 1m square subplots within each treatment. The first weed cover evaluation was on June 19 and 23 and the second was on August 14 and 23, 2006. Grass cover (Figure 1) was highest in the control, postemergence at 222 ml/ha and preemergence at 444 ml/ha treatments for both evaluations. Hexazinone combined with the 222 ml/ha postemergence or 3 oz/a pre and 3 oz/a postemergence mesotrione had the best control of grass cover in both evaluations. The 222 ml/ha pre and postemergence mesotrione treatment without hexazinone on the second evaluation date was statistically the same as with hexazinone. Broadleaf weed cover (Figure 2) was highest in the untreated control and the 222 ml/ha preemergence mesotrione treatment. The combinations of hexazinone with mesotrione resulted in the lowest broadleaf cover ratings as did the 222 ml/ha pre and postemergence combination treatment. The mesotrione applications at the higher rate preemergence or at the low rate pre and post emergence gave equivalent control to the hexazinone application. When these applications were combined with hexazinone additional suppression of both grasses and broadleaf weeds was obtained.

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Figure 1. Grass cover following herbicide treatment, 2006 A 35

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THE ADVANTAGES OF QUINCLORAC OR MESOTRIONE USE IN CRANBERRY BOG ESTABLISHMENT. B.A. Majek, Rutgers Univ., Bridgeton, NJ. ABSTRACT Cranberry bog renovation and establishment in New Jersey is a long term commitment. Currently, some bogs that were established more than seventy five years ago remain in production today. Renovation of a cranberry bog begins at least a year prior to planting. Existing vegetation, including cranberries and weeds are killed, excess peat removed, irrigation mains installed, a uniform sandy soil must be leveled to improve drainage, and dikes, ditches and sluices gates installed. After the bog is prepared, unrooted cranberry cuttings are spread on the bog and sliced into the soil lightly with a disk and irrigated regularly. The cuttings root in two to three weeks. Growers are reluctant to use herbicides during the establishment year, fearing an adverse affect on the crop. Studies were established in bogs planted with cranberry 'Stevens' cuttings in April of 2003 and 2004. Herbicides were applied in late spring, about four weeks after planting, or in the summer, two to three months after planting. Weed growth was heavy in both establishment years, creating a canopy over the cranberry vines by mid summer. The most prevalent weeds were false nutsedge, slender rush, blackgrass, marsh St. Johnswort, large crabgrass, and meadow beauty. When applied four weeks after planting, napropamide suppressed or controlled false nutsedge, slender rush, and large crabgrass, but did not control blackgrass or meadow beauty. The experimental herbicides, quinclorac, chlorimuron, and mesotrione, applied with nonionic surfactant, controlled all the weeds except marsh St. Johnswort when applied four weeks after planting, but were less effective when applied two to three months after planting. The studies were/will be treated annually for three years, until a measurable yield could be harvested from at least some treatments. Napropamide, quinclorac, and mesotrione did not injure the cranberries. The chlorimuron treatment applied annually in late spring appeared to cause slight temporary stunting, and caused some shoot tip chlorosis in 2004. The bog planted in 2003 was harvested in 2005 and in 2006. The bog planted in 2004 was harvested in 2006. All the herbicides applied improved cranberry growth and vigor. The highest yields were observed in cranberries treated annually for three years with quinclorac and mesotrione at 0.5 and 0.2 lb ai/A respectively.

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CHEMICAL CONTROL OF APPLE ROOT SUCKERS WITH COMMERCIAL APPLICATION EQUIPMENT. W.H. Palmer, Reality Research, Williamson, NY. ABSTRACT Controlling root suckers is important to prevent fire blight from entering the apple (Malus domestica) rootstock as well as preventing growth of the suckers up into the tree. Previous results with hand boom applications did not match the results that were being obtained with commercial application equipment. Commercial herbicide application equipment will be described. The trial used commercial equipment to apply treatments of paraquat, glyphosate, 2,4-D, glufosinate, carfentrazone, and a glyphosate/2,4-D premix as 1 or 2 sprays with adjuvants. Results will be presented for sucker control achieved with each treatment. The potential problems of sucker treatments to young fruit trees will also be addressed. Results of the treatments for general weed control will also be presented.

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CHEMICAL CONTROL IN ORCHARDS WITH COMMERCIAL APPLICATION EQUIPMENT. W.H. Palmer, Reality Research; Williamson, NY, and D.I. Breth, Cornell Cooperative Extension, Albion, NY. ABSTRACT Controlling weeds in commercial apple orchards is not a major concern for many New York apple growers. This potentially leads to over-use of herbicides, weed resistance, weed problems at harvest, and negative effects on yields. Previous results with hand boom applications did not match the results that were being obtained with commercial application equipment. Commercial herbicide application equipment will be described. The trial used commercial equipment to apply treatments of several "knockdown" herbicides (paraquat, glyphosate, 2,4-D, glufosinate, carfentrazone, and a glyphosate/2,4-D premix) as 1 or 2 sprays with adjuvants. The trial also includes applications of the “knock-down” herbicides with residual herbicides (simazine, diuron, pendimethalin and flumioxazin. Results will be presented as season-long weed evaluations with each treatment. Other reasons for good orchard weed control will be presented, along with one grower's ideal control program that includes leaving some “friendly” weeds in the orchard.

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STRAWBERRY PLANTING YEAR WEED CONTROL: THE NEED FOR ADDITIONAL HERBICIDES. C.A. Benedict and R.R. Bellinder, Cornell Univ., Ithaca, NY. ABSTRACT Weed control in the year of planting is a major issue facing strawberry growers. In a recent survey, growers placed weeds as the highest of their concerns during the establishment year. Planting year weed control is essential to both minimize weed competition and to maximize yield in the fruiting years. With few herbicides registered for strawberries in the planting year, reliance on costly hand-weeding can become a serious economic drain. Field and greenhouse studies were initiated to determine compatibility of new herbicides. In the greenhouse, herbicides were applied using an Allen Track Sprayer (Midland, MI) at 25 GPA. In these trials, over 15 herbicides were evaluated postemergence (POST), pretransplant (PRETP), or for impact on runner development/rooting. Injury was observed PRETP with fomesafen (0.626 lb ai/A) and smetolachlor (1.3, 2.6 lb). Injury PSTTP was observed with oxyfluorfen (2XL 0.5, 4F 0.5 lb), flumioxazin (0.03, 0.06 lb), halosulfuron (0.092 lb), and in combinations of smetolachlor (0.094 lb) + flumioxazin (0.03 lb) and KIH-485 (0.113 lb) + oxyfluorfen (4F 0.375 lb). Runner injury, root development, and dry wt reduction were observed with smetolachlor (1.3 lb) and KIH-485 (0.226 lb). In a field trial, 'Earliglow' and ‘Jewel’ were utilized to evaluate ten products either PRETP or PSTTP. All applications were made using a CO2 backpack sprayer set to deliver 34 GPA. Oxyfluorfen (4F 0.375 lb) caused initial injury on ‘Earliglow’. Other notable injury occurred in KIH-485 (0.226 lb PSTTP) and flumioxazin (0.03 lb PRETP). Runner production decreased with flumioxazin (0.03 lb PRETP), penoxsulam (0.026 lb PSTTP), and V-10142 (0.1 lb PSTTP) treatments.

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BEING HEARD BY THE IR-4 PROJECT. E. Lurvey, Northeast Region IR-4 Project, Cornell NYSAES, Geneva, NY. ABSTRACT The mission of IR-4 is to support the registration of pest management tools for specialty crops such as fruits, vegetables and ornamental horticulture. Pest management tools include conventional pesticides as well as biological control agents (biopesticides). The IR-4 research process is dependent on the active participation of growers, researchers, extension personnel, and other client groups. First, only clients without vested interests can submit a Project Clearance Request Form (PCR), either through the IR-4 Northeast Region Field Coordinator (RFC), Edith Lurvey, the IR-4 website (http://ir4.rutgers.edu/) or the appropriate IR-4 State Liaison Representative. The PCR is the first step in the process to get the pest management use on the IR-4 agenda for consideration. Only Par's that have been agreed to by the product registrant will be eligible for consideration at the IR-4 Priority Setting Workshops in September and October. Prior to either workshop, the IR-4 Northeast Region Field Coordinator solicits input on the important needs from growers and researchers in the region. No project is given a high priority without a regional champion. Priorities are as follows: A priorities will have research started in the following growing season: B priorities may be researched as funds allow; C priorities are kept on the researchable project list for future consideration. Food Use prioritization: An additional step was added to the Food Use process this year. All projects to be discussed in a given year must now be nominated prior to the workshop in September. This entails going to the IR-4 website a few weeks prior to the workshop and selecting chemical/crop uses from the researchable projects list. Any project not nominated for three years in a row will be dropped from the IR-4 active list, and would need a new PCR to be reactivated. Growers, researchers, extension workers, etc., need to contact the RFC directly for any project needing a high priority (A or B Priority). Ornamental Horticulture prioritization: A, B and C priorities are established focusing on a specific pest or production need. These priorities are arrived at by consensus among the participants from the four IR-4 regions, with some attention is paid to projects of regional importance. For example, the 2007 national weed science priority is phytotoxicity of several herbicides in perennial nursery plants, with a regional priority (southern and western) for efficacy in the control of sedges in nursery production. Please note that the Northeast region solicits input via email on regional priorities prior to the workshop. Final selection of regional A priorities is made via a teleconference, if needed. If you would like to be added to the list serve for these calls for input, please contact the RFC, Edith Lurvey ([email protected]). Biopesticide projects continue to be selected as competitive grants for proposals.

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WEED CONTROL IN NO-TILL PUMPKINS. D.H. Johnson, The Pennsylvania State Univ., Manheim and D.D. Lingenfelter, The Pennsylvania State Univ., University Park. ABSTRACT Weed control and pumpkin (Cucurbita maxima) injury from several products were tested in no-till production at two locations in Pennsylvania. Pumpkins (cv. 'Spirit' and ‘Sugar or Pie’) were planted no-till into previously killed (glyphosate) and rolled rye in Lancaster (Landisville) and Centre (Rock Springs) Counties, respectively, in mid June. Several herbicides were applied preemergence just after planting, followed by postemergence herbicides approximately one month later. Most herbicides tested are not currently labeled for pumpkin production. These were flumioxazin (0.08 lb ai/A), imazamox (0.03 lb ai/A), rimsulfuron (0.047 lb ai/A), and fomesafen (0.375 lb ai/A), all applied preemergence in A tank mix with dimethenamid-P (0.75 lb ai/A), KIH-485 (0.16 lb ai/A) applied preemergence alone, or imazamox (0.03 lb ai/A) applied postemergence. Additional treatments included standards: clomazone (0.49 lb ai/A) + ethalfluralin (0.75 lb ai/A) + halosulfuron-methyl (0.035 lb ai/A) applied pre, halosulfuronmethyl pre followed by clethodim (0.125 lb ai/A) postemergence, or halosulfuron-methyl + clethodim post. Weed control, crop injury, and pumpkin yield were determined. Studies were arranged in a randomized complete block design with three replications. Flumioxazin and rimsulfuron (both tank mixed with dimethenamid-P) caused high pumpkin injury (up to 78%) and yield loss at Landisville. Injury was lower (45%) at Rock Springs, and yield was not significantly reduced. The other products did not cause significant crop injury. Weed control at Rock Springs was generally better than at Landisville. At Rock Springs, the standards clomazone + ethalfluralin + halosulfuron-methyl gave 90% or better velvetleaf (Abutilon theophrasti), common ragweed (Ambrosia artemisiifolia), yellow nutsedge (Cyperus esculentus), and giant foxtail (Setaria faberi) control. The combinations of newer herbicides plus dimethenamid-P and KIH-485 applied alone gave similar control for all of these except yellow nutsedge. Imazamox + dimethenamid-P was also weak on common ragweed. At Landisville, clomazone + ethalfluralin + halosulfuron-methyl gave only 45 and 77% common lambsquarters (Chenopodium album) and fall panicum (Panicum dichotomiflorum) control, respectively. Most combinations of newer herbicides with dimethenamid-P gave better control. These results show dimethenamid-P, imazamox, fomesafen, and KIH-485 have potential for weed control in pumpkins with good crop safety. More testing on other pumpkin varieties and in other climates and soils would need to be done to ensure adequate crop safety.

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EVALUATING TRIKETONES IN SWEET CORN. R.R. Bellinder and C.A. Benedict, Cornell Univ., Ithaca, NY. ABSTRACT Effective postemergence (POST) weed control is essential when preemergence (PRE) herbicides fail. New triketone herbicides for use POST are available, but their effectiveness has not been thoroughly tested. In 2006, five field trials evaluated weed control and varietal tolerance to mesotrione, tembotrione, and topramezone. Weed pressure at the time of application was heavy and highly uneven across trials. Broadleaf weed control was variable based on product and surfactants. Broadleaf weed control decreased with all three triketones (1X rate) when they were applied without atrazine. At the 1X rate, tembotrione and topramezone provided adequate control of redroot pigweed (Amaranthus retroflexus L.), common lambsquarters (Chenopodium album L.), and common ragweed (Ambrosia artemisiifolia L.). Tembotrione at the 2X rate provided better broadleaf control than did 2X rates of mesotrione and topramezone. Foxtail species (Setaria spp.) were common in all trials, but large crabgrass (Digitaria sanguinalis (L.) Scop.) populations were variable. Mesotrione inadequately controlled crabgrass in one trial; however control increased with rate and addition of atrazine. Due to their large size (8-12 in.) at the time of application Setaria spp. control was inadequate regardless of rate. Weed control was better when MSO was used with atrazine, topramezone, and UAN than when a non-ionic surfactant was used. Tembotrione controlled crabgrass adequately at 6 DAT, but control broke at 21 however, adding atrazine increased control with the 1X rate substantially. A field trial evaluated ten varieties for crop tolerance. Two varieties, 'Argent' and ‘Silverking’ showed initial sensitivity to all three of the triketones, but outgrew this injury. There was no reduction in weight in any of these varieties. In another trial, there was a decrease in ear number and total weight with a 2X rate of mesotrione. Ongoing greenhouse trials are taking a closer look at the application timing of these herbicides for control of annual broadleaves and grasses. Preliminary results suggest that timing is crucial to the effectiveness of these herbicides.

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NATURAL PRODUCT POTENTIAL FOR WEED CONTROL IN POTATO. G.J. Evans and R.R. Bellinder, Cornell Univ., Ithaca NY. ABSTRACT Weed management in organic potato production relies heavily on cultivation and hilling. Excessive cultivation can have negative impacts on soil structure, encourage new flushes of weeds, and require high fossil fuel consumption. Our objective is to evaluate the potential use of acetic acid (vinegar) and Matran II (clove oil) with regard to how product volume, concentration, and application timing effect weed control and crop response. Two trials were conducted in 2006 at the Thompson Research Farm in Freeville, NY. Treatments included: 20 and 30% acetic acid applications at 34 GPA, 15 and 20% acetic acid applications at 68 GPA, a 10% dilution of Matran II in water, and a 5% dilution of Matran II in 20% acetic acid. Acetic acid treatments included yucca extract at 0.1% V/V, and Matran II treatments contained 2.5% humasol. Both trials included a handweeded control and a weedy check. Treatments were broadcast at either an early (10 cm) or late (30 cm) timing. Late timing plots were cultivated once 19 days before treatment. Applications were applied with a CO2 backpack sprayer. Weed species common to all plots of a given trial were marked prior to spraying, and aboveground biomass was harvested 12-15 DAT, dried and weighed. Ratings were taken for weed control, weed regrowth, crop injury, and yield. The 15% acetic acid treatment caused 83 and 39% injury with the early and late timing applications, respectively. However, by 30 DAT visual injury was outgrown in all treatments except 20% acetic acid (68 GPA), regardless of application timing. Yield reductions relative to handweeded treatments occurred in both trials, and were significant with late applications of acetic acid applied at 68 GPA, and the 5% Matran in 20% acetic acid. Treatment yields with 20% acetic acid at 34 GPA were reduced by an average of 11%, while yields with 20% acetic acid at 68 GPA were reduced by 21%. Weed control varied by species, weed size, and treatment. When rated 1 DAT, 15% acetic acid (68 GPA) provided between 53 and 99% control of common lambsquarters (Chenopodium album), common chickweed (Stellaria media), wild buckwheat (Polygonum convolvulus), redroot pigweed (Amaranthus retroflexus), hairy galinsoga (Galinsoga ciliata) and large crabgrass (Digitaria sanguinalis). Peak weed control, 84 and 99%, occurred with the smallest size species, redroot pigweed (4 leaves) and hairy galinsoga (2 leaves), respectively. By 14 DAT, there was no appreciable biomass reduction of large crabgrass when treated at 2-3 leaves. Overall product effectiveness depends on the severity of weed pressure and weed species composition, with smaller broadleaf species most susceptible to control. Although Matran II was much less injurious to potato, it is more costly and less effective at controlling weeds compared to acetic acid. Yield reductions may be acceptable with some treatments, particularly if these can be offset by reduced weed management costs or the higher returns expected for organically grown potatoes.

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WEED CONTROL IN NO-TILL SWEET CORN. D.D. Lingenfelter, The Pennsylvania State Univ., University Park and D.H. Johnson, The Pennsylvania State Univ., Manheim. ABSTRACT Field studies were conducted in 2006 at two locations in PA to evaluate annual and perennial weed control in no-till sweet corn (Zea mays L., succharata var. 'Attribute'). Atrazine (1.24 lb ai/A) and s-metolachlor (0.96 lb ai/A) were applied PRE to most of the treatments followed by a POST application of one or a combination of the following herbicides: 2,4-D (0.25 to 0.5 lb ai/A), atrazine (0.25 to 0.5 lb ai/A), bentazon (0.52 lb ai/A), mesotrione (0.094 lb ai/A), topramezone (0.0164 lb ai/A), tembotrione (0.12 lb ai/A), carfentrazone (0.012 lb ai/A), clopyralid (0.19 lb ai/A), halosulfuron (0.032 lb ai/A), foramsulfuron (0.033 lb ai/A), glufosinate (0.4 lb ai/A), and KIH-485 (0.18 lb ai/A). Adjuvants were included in the POST spray mixtures. In general, herbicide treatments provided >90% control of annual weeds including, giant foxtail (Setaria faberi), fall panicum (Panicum dichotomiflorum), common lambsquarters (Chenopodium album), and velvetleaf (Abutilon theophrasti). Canada thistle (Cirsium arvense) was the only perennial weed species that was common at both locations. Clopyralid, mesotrione plus atrazine, and glufosinate plus atrazine provided 80 to 85% control of Canada thistle. Other treatments that provided >80% control of Canada thistle included, tembotrione plus atrazine (92%) at Rock Springs and topramezone plus atrazine (83%) at Landisville. At Landisville, field bindweed (Convolvulus arvensis) control ranged from 82 to 92% control with treatments containing 2,4-D, clopyralid, and glufosinate plus atrazine, while the other treatments only provided 45 to 77% control. At Rock Springs, tembotrione plus atrazine, halosulfuron plus 2,4-D, and foramsulfuron provided between 70 and 81% control of hemp dogbane (Apocynum cannabinum) and common milkweed (Asclepias syriaca). Glufosinate plus atrazine also provided adequate suppression (80%) of hemp dogbane. Aside from carfentrazone, clopyralid, and KIH-485, most of the other POST treatments provided 77 to 95% control of common pokeweed (Phytolacca americana). No crop injury occurred from any of the treatments at Landisville. At Rock Springs, negligible crop injury was noted on most treatments except for halosulfuron plus 2,4-D and foramsulfuron which ranged from 15 to 20%. Sweet corn yields at Rock Springs were generally better than at Landisville. At Rock Springs, sweet corn in the untreated check yielded about 5,300 lb/A compared to the other treatments which ranged from 9,100 to 13,000 lb/A. The one exception was the halosulfuron plus 2,4-D treatment which reduced the yield to about 5,800 lb/A. At Landisville, sweet corn yields also benefited from better weed control in the herbicide treated plots and ranged from about 5,800 to 9,000 lb/A compared to the untreated check (2,700 lb/A). In summary, production of no-till sweet corn can be enhanced by newer herbicide options. Compared to a decade ago, PRE and POST annual weed control in sweet corn has greatly improved. Perennial weed control can still be challenging for sweet corn producers, especially in no-till settings. However, with the introduction of some newer herbicide chemistries, these can complement other product choices to provide better weed management.

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THE IR-4 PROJECT: UPDATE ON HERBICIDE REGISTRATION. M. Arsenovic, F.P. Salzman, D.L. Kunkel, and J.J. Baron, IR-4 Project, Rutgers, The State Univ. of New Jersey. Princeton. ABSTRACT The IR-4 Project is a publicly funded effort to support the registration of pest control products on specialty crops. The IR-4 Project continues to meet grower's needs for weed control options, primarily with mature-market herbicides since the adequate selectivity of specialty crops to many of the recently introduced herbicides remains a challenge. The Pesticide Registration Improvement Act (PRIA) continues to effect IR-4 submissions and EPA review of packages. IR-4 submitted herbicide petitions to the EPA from October 2005 to September 2006 for: desmedipham on garden beet and spinach; foramsulfuron + isoxadifen-ethyl on sweet corn and popcorn; mesotrione on cranberry; pronamide on chicory, Belgian endive, dandelion, and berry group; and smetolachlor on winter squash and pumpkin. From October 2005 through September 2006, EPA has published Notices of Filing in the Federal Register for: bentazon on peach and nectarine; clethodim on leafy greens subgroup, cilantro, legume vegetable group, herb subgroup, asparagus, flax, hops, safflower, and sesame; desmedipham on garden beet and spinach; dimethenamid on leek, green onion, Welsh onion, shallot (fresh leaves), grass (forage, fodder, and hay) group; diuron on prickly pear cactus and mint; ethofumesate on carrot (use in Washington and Oregon), garden beet, dry bulb onion, garlic, shallot (bulb and fresh leaves); fluroxypyr on dry bulb onion, shallot (bulb), and garlic; fomesafen on dry bean and snap bean; glyphosate on safflower, sunflower, Indian mulberry, and legume vegetable (except soybean) group; lactofen on fruiting vegetable group and okra (Southeast only); mesotrione on cranberry; pendimethalin on green onion, leek, Welsh onion, shallot (fresh leaves), fruiting vegetable group, pome fruit group, stone fruit group, juneberry, pomegranate, and strawberry (perennial); phenmedipham on spinach; sethoxydim on root vegetable (except sugar beet) subgroup, radish tops, turnip tops, buckwheat, borage, dill, and okra; and s-metolachlor on pumpkin and winter squash. EPA established tolerances from October 2005 though September 2006 for: dimethenamid on green onion, leek, Welsh onion, and shallot (fresh leaves); ethofumesate on carrot (use in Washington and Oregon), garden beet, dry bulb onion, garlic, shallot (bulb and fresh leaves); fomesafen on dry bean and snap bean; flumioxazin on strawberry; paraquat on cucurbit vegetable, dry bulb onion, ginger, and okra; pendimethalin on carrot, citrus fruit group, tree nut group, pistachio, mint, green onion, leek, Welsh onion, shallot (fresh leaves), fruiting vegetable group, pome fruit group, juneberry, pomegranate, and strawberry (perennial); s-metolachlor on pumpkin and winter squash; and terbacil on watermelon.

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ORNAMENTAL WORKSHOP 2007. J. Altland, Moderator, Oregon State Univ., North Willamette Research and Education Center, Aurora. ABSTRACT A workshop format will be used in discussing the topic of “Research Methods for Weed Management in Container Crops”. Participants have been in invited to introduce and help lead a discussion on three areas of interest by researchers working in weed control in ornamentals. Following the introduction by the group moderator all workshop participants will have an opportunity to provide ideas and examples of their methods used when conducting trials. The workshop is for the benefit of participants and it is planned that a “Notes on Research Methodologies in Ornamental Weed Science’ will be summarized and distributed to all that attend. Topics to be discussed – come prepared to share resources and ideas: 1. 2.

3.

Methods for collecting, cleaning, drying and storing weed seed. Handling those hard to find seeds. Conducting bioassays. How do you inoculate or “seed” pots with weeds? What methods have worked better? Should pots have both weed population and ornamental plant placed for evaluation in the same pot? What types of statistical designs are used? Maintaining weed populations for the length of study. What are the best methods to evaluate residual control from a preemergmence application? What evaluations are best used for weed control and for plant safety? What parameters are best used to examine plant tolerance; what observations best describe the plant phytotoxicity that is identified? What size plant do you use and when do you make your application; directly after transplanting, etc? Does requiring multiple applications add to information on plant safety? How does working with trees or field-grown plants change your application methods, age of plant or other parameters in plant safety trials?

Discussions may use specific weed species like creeping woodsorrel or liverwort or other emerging nursery weed problems as examples in the discussions. Also, in the discussions on looking at plant tolerance examples of plants that are recognized as more “chemical sensitive” vs. those species where plant injury is seldom seen may be used as examples in the discussions. Each topic will have at least 3 participants who have come prepared to share their information on that topic. Two industry spokespeople will share briefly their viewpoint on executing ornamental research trials and company expectations from the data generated. However, participation from the audience is being encouraged for all topics.

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PEDIGREE OF A PESTICIDE. D.R. Spak and N.M. Hamon, Bayer Environmental Science, Research Triangle Park, Raleigh, NC. ABSTRACT This presentation takes the audience through a 10 to 20-year journey from the discovery through to the commercialization and growth of a new agrochemical. It attempts to explain the dramatic consolidation in the industry, addressing costs, competition, the challenging regulatory environment, patents and intellectual property and the influence of biotechnology on the market. The presentation shows the science and complexity of identifying a new active ingredient and the exhaustive testing required to get it to the market place. Also addressed is the innovation required to keep older chemistry competitive.

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HOW GOLF COURSE SUPERINTENDENTS VIEW NEW HERBICIDE COMPOUNDS. S. Zontek, United States Golf Association, Glen Mills, PA. ABSTRACT One of the basic prerequisites of a good golf course is a weed-free turf. It is basic. The game of golf is played on grass, not weeds. Golfers (usually) cannot distinguish between most weed grasses growing in the desired turfgrass stand. They can distinguish between weeds like crabgrass (Digitaria sanguinalis (L.) Scop.), goosegrass (Eleusine indica (L.) Gaetn), dandelions (Taraxacum officinale Weber), dallisgrass (Paspalum dilatatum Poir) and Poa annua, during the period of the year when it produces seedheads. Therefore, golf course superintendents are interested in controlling the weeds. Golf course superintendents tend to embrace new herbicide chemistries. They understand that a well conditioned golf course is a positive reflection on their work and their programs. The reverse is also true. No golf course superintendent likes complaints as in not being able to find a golf ball that lands in the rough due to a thick mat of clover or the seed pods from dandelions. Also, grassy weeds present uniformity as well as playability issues in roughs. Right or wrong, today’s golfers desire roughs which are consistent. Weeds in rough present a stand of grass that can (and is) inconsistent both in terms of appearance and playability. Therefore, controlling weeds is a priority for golf course superintendents for practical as well as perceptive reasons. A well presented golf course, free of weeds with a healthy stand of turfgrass, is pleasing to most golfers. Equally, the reverse is true. This presentation will be an attempt to discuss the latest herbicide chemistries on how they are being used by golf course superintendents in the Eastern Transition Zone and MidAtlantic Region of the United States. Herbicide compounds to be discussed are the latest suggested usage for the older chemistries of broadleaf and annual grassy weed controls as well as how superintendents are using the latest chemistries of weeds including the ALS inhibitors.

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SEEDHEAD SUPPRESSION OF ANNUAL BLUEGRASS. J.A. Borger and M.B. Naedel, The Pennsylvania State Univ., University Park. ABSTRACT Annual bluegrass is commonly found on golf courses today. Many turfgrass managers choose to maintain annual bluegrass while others try to eliminate it. Annual bluegrass can produce many seedheads in the spring, regardless of mowing height. Seedhead production can create an undesirable sward for a variety of reasons. First, seedheads can be aesthetically displeasing resulting from an off white color during the peak production period. This production of annual bluegrass seedheads may result in a decrease of plant health. Additional stress, such as traffic or lack of moisture, may lead to an undesirable sward. Second, annual bluegrass seedheads may adversely affect turfgrass playability, especially in regards to a golf course putting green. Ball roll and smoothness are often compromised by annual bluegrass seedheads. Chemical applications of plant growth regulators and other materials have been used for the suppression of annual bluegrass seedheads. The correct timing of the application of these materials are imperative. If applications are made too early and temperatures are not optimal for growing conditions, plant health may be an issue. If materials are applied too late in the season, seedhead suppression may not be accomplished. Material application timings can differ. A common material application timing is when the annual bluegrass is in the boot stage of development. The boot stage should be monitored by sampling annual bluegrass plants in different areas of the overall sward. Many studies have been conducted to evaluate various plant growth regulators for the suppression of annual bluegrass seedheads. For example, Embark T&O is a growth regulator which provides excellent suppression when applied at the correct rate and timing. Other options include a tank mix of Primo Maxx and Proxy. This tank mix has shown good suppression in several studies. Researchers continue to evaluate new products, product combinations, and application timings to better suppress annual bluegrass seedheads.

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BISPYRIBAC-SODIUM (VELOCITY) USE ON GOLF COURSES FOR ANNUAL BLUEGRASS AND ROUGHSTALK BLUEGRASS CONTROL. S.E. Hart and P.E. McCullough, Rutgers, The State University of New Jersey, New Brunswick. ABSTRACT Bispyribac-sodium (hereafter referred to as bispyribac) herbicide represents on of the most significant advancements for the selective control of annual bluegrass in coolseason turfgrass. Studies conducted at Rutgers University have determined that latespring/early summer is the timing for bispyribac application for optimum annual bluegrass control and creeping bentgrass safety. Applications in cool weather conditions provided significantly less annual bluegrass control with marginal creeping bentgrass safety. Studies have also been conducted on the response of other cool-season turfgrass species to bispyribac which demonstrated the potential to severely injure Kentucky bluegrass. Kentucky bluegrass may not adequately tolerate bispyribac at rates necessary for annual bluegrass control. Perennial ryegrass, tall fescue, and fine fescue may show initial symptoms of injury, but levels are less severe and persistent than those exhibited by Kentucky bluegrass. Bispyribac should be safe to use on perennial ryegrass, tall fescue, and fine fescue for annual bluegrass control. Additional studies have also determined that all cool-season turfgrass species, including creeping bentgrass, can be rapidly reseeded (within 10-14 days) into areas treated with bispyribac. This should allow for the potential use of bispyribac in fairway renovation to convert mixed annual bluegrass/creeping bentgrass fairways to predominately creeping bentgrass. Lastly we have been conducting studies on the long-term control of roughstalk bluegrass with bispyribac. Initial activity is high, however we have observed substantial regrowth of roughstalk bluegrass the following year. We are also currently conducting studies evaluating the influence of golf course management practices on the efficacy and safety of bispyribac as well as its potential use on bentgrass putting greens.

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APPLICATIONS FOR SULFENTRAZONE USE ON GOLF TURFS. S.J. McDonald, Turfgrass Disease Solutions, Pottstown, PA and P.H. Dernoeden, Univ. of Maryland, College Park. ABSTRACT Sulfentrazone was labeled for use on turfgrasses in 2006 and is sold under the trade name of Dismiss®. According to the label, creeping bentgrass (Agrostis stolonifera), red fescue (Festuca rubra), tall fescue (Festuca arundinacea), perennial ryegrass (Lolium perenne), Kentucky bluegrass (Poa pratensis), bermudagrass (Cynodon dactylon) and zoysiagrass (Zoysia japonica) are tolerant of sulfentrazone. The label, however, does not specify different rates based on turfgrass species. The herbicide’s primary use in turf is for postemergence control of yellow and purple nutsedge (Cyperus spp.), and green and false green Kyllinga (Kyllinga spp.). Numerous broadleaf weed species are listed as being controlled or suppressed. To our knowledge, this herbicide has not been formally evaluated for use on turfgrasses in the Philadelphia to Washington D.C. corridor. Initial studies in College Park, MD, showed that sulfentrazone (0.375 lb ai/A) applied in May 2006 was highly effective in controlling yellow nutsedge (C. esculentus) in perennial ryegrass maintained to a height of 2.5 inches. On creeping bentgrass golf course fairways maintained to a height of 0.5 inches in Lothian, MD a single application of sulfentrazone in July killed exposed leaves, but the yellow nutsedge recovered either from stems or tubers. The aforementioned observation suggests that under low mowing insufficient leaf area is exposed, which may result in less herbicide uptake and therefore inadequate translocation of active ingredient to stems and tubers. Sulfentrazone (0.125, 0.250, and 0.375 lb ai/A) was applied once in August 2006 to “Crenshaw’ creeping bentgrass and Tufcote bermudagrass maintained at 0.5 inches in College Park and no injury was observed. The same rates applied to ‘Zenith’ zoysiagrass maintained at 0.5 inches elicited an objectionable level of injury for about two weeks, especially the high rate. Sulfentrazone (0.125, 0.250, and 0.375 lb ai/A) was applied either once or twice to a golf course fairway in Pottstown, PA beginning on 17 August and sequential treatments were applied 31 August 2006. The fairway consisted of approximately 45% creeping bentgrass, 30% perennial ryegrass, 5% annual bluegrass (Poa annua) and 20% goosegrass (Eleusine indica). The 6 to 8 tiller, seedhead bearing goosegrass was severely injured, but even at the highest rate (0.375 + 0.375 lb ai/A) only 42% control was achieved. Sulfentrazone elicited unacceptable injury to the perennial ryegrass following the sequential application at the highest two rates. Injury to creeping bentgrass was slightly objectionable following the sequential application of the high rate. While the level of goosegrass control was poor, data and observations suggest that an earlier sulfentrazone application to less mature goosegrass may be effective. More research also is needed to elucidate the impact of mowing height and application timing on sulfentrazone performance and the influence of air temperature on the sensitivity of mid-Atlantic turfgrasses to this herbicide.

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SELECTIVE REMOVAL OF CREEPING BENTGRASS WITH MESOTRIONE. J.E. Kaminski, Univ. of Connecticut, Storrs. ABSTRACT Creeping bentgrass (Agrostis stolonifera L.) is a major weed problem in home lawns, athletic fields, and golf course roughs. The influence of mesotrione and triclopyr were assessed for their ability to selectively remove creeping bentgrass from Kentucky bluegrass (Poa pratensis L.). This study was conducted at the University of Connecticut Plant Science Research and Education Facility located in Storrs, CT. An average of 39% creeping bentgrass was present when the study was initiated. Triclopyr and mesotrione each were applied at two rates on a 14-day interval for a total of two, three or four applications. All treatments were applied using a CO2 pressurized sprayer calibrated to deliver 467 l/ha water. Regardless of herbicide rate, all plots treated with triclopyr and mesotrione exhibited significant injury with 4 and 7 days following treatment, respectively. Three months after the initial treatment (19 September), creeping bentgrass populations within all herbicide-treated plots were reduced when compared to the untreated control. On most rating dates, excellent control (≤ 5% bentgrass) was achieved within plots receiving ≥ 3 applications of mesotrione (0.125 and 0.187 lb ai/A) and three (1.0 lb ai/A) or four (0.5 and 1.0 lb ai/A) applications of triclopyr. Plots treated with two applications of mesotrione (0.187 lb ai/A) resulted in moderate levels of creeping bentgrass control. On the final rating date, there were no differences in creeping bentgrass cover among plots treated with two (0.5 and 1.0 lb ai/A) or three (0.5 lb ai/A) applications of triclopyr or two applications of mesotrione (0.125 oz lb ai/A) and the untreated control. Unlike triclopyr, mesotrione did not appear to inhibit regrowth of Kentucky bluegrass into areas void of turf.

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HORSEWEED: FROM OBSCURITY TO THE LIMELIGHT. M.J. VanGessel, Univ. of Delaware, Georgetown. ABSTRACT Horseweed (Conyza canadensis) is a ubiquitous plant species found in temperate climates world-wide. It infests crops grown under no-tillage production and in perennial crops. In 2000, plants found in Delaware were identified as resistant to glyphosate. It was the first report of a broadleaf weed resistant to glyphosate. Since that time, a number of research programs have had an interest in studying this species. Based on electronic databases of scientific journals, well over half of the studies listing horseweed in the title or as a keyword (~60%) were published since 2001. While this recent interest in horseweed is not exclusive to the presence of glyphosate-resistant biotypes, most of the ecology and biology based studies of this species cite resistance as a justification for conducting the trials. Horseweed research since 2001 has become more expansive and often focuses on horseweed, rather than identifying horseweed as one of the species present at the experimental site

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HOW THE SPATIAL SCALE OF DISPERSAL MODELING HAS INCREASED WITH GLYPHOSATE-RESISTANT HORSEWEED. J.T. Dauer, D.A. Mortensen, The Pennsylvania State Univ., University Park, E.C. Luschei, Univ. of Wisconsin, Madison, M.J. VanGessel, Univ. of Delaware, Georgetown, and E.S. Shields, Cornell Univ., Ithaca, NY. ABSTRACT Population dynamics modeling of species spread often assume no vector assisted movement and can be represented using cellular automata models where a population contributes genes, seeds or pollen, to nearest neighboring cells. In the simplest sense, these models can be adjusted to include vectored movement by increasing the probability of seed landing at long distances. This method ignores the underlying mechanisms of vectored movement and fails to accurately simulate longdistance dispersal. The importance of glyphosate-resistant horseweed has generated interest in quantifying the likelihood that seed are being distributed to nearest neighbor fields versus long-distance dispersal. Instead of a cellular approach, we defined the landscape by a series of polygons outlining actual fields in a 10 km x 9 km aerial photo of Pennsylvania cropland. Polygons were assigned initial crop type, corn or soybean, which were rotated yearly and impacted the survivorship of seed that arrived in the previous time step. A 2-dimensional 2-parameter dispersal model dependent on distance from the source and source strength was applied to seed movement in the landscape. Dispersal was normalized by area to determine seed arrival in every field in the landscape. Survivorship varied from zero percent (best management with alternative herbicides, tillage) to 100 percent (glyphosate only). Simulations conducted thus far have not included a directional wind vector but will be included as the model advances. Spread from randomly initiated source fields was slow for three years, increasing source strength but spreading less than 1 km per year. In the fourth and fifth years after initiation, seed dispersal and establishment reached fields at the extent of the described landscape (at least 5 km). Continued manipulation of the model will explore the importance of field size and quantify the necessary efficacy to reduce spread to less than 1 km per year. The ability of horseweed seed to disperse long distances has enlarged the scale at which resistance management can have an impact. Focusing on a single field or a small region will not prevent spread of this biotype to neighboring farms. As more species develop resistance to glyphosate, questions about how to reduce the impact will require predictive models created on the correct spatial scale.

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RECENT FINDINGS ON THE FIELD BEHAVIOR, GENETICS, AND MECHANISM OF GLYPHOSATE-RESISTANCE IN HORSEWEED. D.I. Gustafson, M.T. Faletti, G.R. Heck, R.D. Sammons, and M.B. Spaur, Monsanto Company, St. Louis, MO. ABSTRACT We have undertaken a series of investigations to help understand the field behavior, genetics, and mechanism of glyphosate-resistance in horseweed (Conyza canadensis). Our on-going field studies are focused on the long-term impact of various agronomic practices on horseweed populations, such as crop rotation, use of coherbicides, and tillage. We have also studied the relative fitness of resistant and sensitive biotypes under field conditions. Our genetics studies show that glyphosate-resistance in horseweed is inherited through a single nuclear gene, one that is either wholly or partially dominant. We have further investigated whether target site mutation can be implicated as a mechanism for glyphosate resistance in horseweed. Three EPSPS (5-enol-pyruvylshikimate-3phosphate synthase) genes were found in the species and identical amino acid sequences were determined for the corresponding genes in both sensitive and resistant biotypes. Expression of these genes was comparable in response to glyphosate and in gross organ distribution across the biotypes, leading to the conclusion that glyphosate resistance in horseweed is not due to EPSPS target site mutation, overexpression or gene amplification. Instead, our mechanism research shows that translocation of glyphosate in the resistant biotype is reduced, relative to the sensitive biotype. The biomolecular process responsible for this phenomenon is the subject of current research, both at Monsanto and at other institutions. A number of potential hypotheses have been investigated and will be discussed. Taken together, our findings have many practical implications for growers attempting to manage this important weed. In particular, our results suggest that timely applications of glyphosate and auxin-type herbicides at sufficient rates should be extremely effective in reducing populations of the resistant biotype.

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HORSEWEED EMERGENCE, SURVIVAL, AND SEEDBANK DYNAMICS IN SOUTHEASTERN INDIANA AGROECOSYSTEMS. W.G. Johnson, V.M. Davis, and K.D. Gibson, Purdue Univ., West Lafayette, IN. ABSTRACT Horseweed (Conyza canadensis) is an increasingly common and problematic weed in no-till soybean production in the eastern cornbelt due to the frequent occurrence of biotypes resistant to glyphosate. The objective of this study was to determine the influence of crop rotation, winter wheat cover crops (WWCC), residual non-glyphosate herbicides, and burndown application timing on the population dynamics of glyphosate resistant (GR) horseweed and crop yield. A field study was conducted from 2003 to 2005 in a no-till field located at a site that contained a moderate infestation of GR horseweed (approximately 1 plant m-2). The experiment was a splitplot design with crop rotation (soybean-corn or soybean-soybean) as main plots and management systems as subplots. Management systems were evaluated by quantifying in-field horseweed plant density, seedbank density, and crop yield. Horseweed densities were collected at one month after spring applied burndown herbicides (MAB), one month after postemergence applications (MAP), and at the time of crop harvest or 4 MAP. Viable seedbank densities were also evaluated from soil samples collected in the spring prior to germination, in the summer prior to seed rain, and in the fall following seed rain. Crop rotation did not influence in-field horseweed or seedbank densities at any data census timing. Burndown herbicides applied in the spring were more effective at reducing horseweed plant densities than when applied in the previous fall. Spring-applied, residual herbicide systems were the most effective at reducing season long in-field horseweed densities and protecting crop yields since horseweed in this region behaves primarily as a spring emerging summer annual weed. Horseweed seedbank densities declined rapidly in the soil by an average of 76% for all systems over the first ten months prior to new seed rain. Despite rapid decline in total seedbank density, seed for GR biotypes remained in the seedbank for at least two years. Therefore, to reduce the presence of GR horseweed biotypes in a local no-till weed flora, integrated weed management (IWM) systems should be developed to reduce total horseweed populations based on the knowledge that seed for GR biotypes are as persistent in the seed bank as GS biotypes.

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HORSEWEED RESPONSE TO NO-TILL PRODUCTION SYSTEMS. M.J. VanGessel, B.A. Scott, Q.R. Johnson and S.E. White, Univ. of Delaware, Georgetown. ABSTRACT Horseweed (Conyza canadensis) has been a common weed in no-tillage production systems in Delaware since the adoption of no-till. In 2000, horseweed plants from multiple fields in DE were identified as resistant to glyphosate. Since then glyphosate-resistant biotypes have become wide-spread and have forced farmers to find an alternative to glyphosate for its control. Fields planted with no-till corn in DE are often treated with paraquat and simazine during the early spring and this provides effective control. Thus, research has focused on horseweed management in soybeans. A series of studies were conducted at the University of Delaware to examine horseweed response to various management practices and the environmental impacts on horseweed growth and development. Horseweed plants at three stages of growth (seedling, large rosettes, and bolting) were treated in the greenhouse with various rates of glyphosate. Glyphosatesusceptible plants were effectively controlled, regardless of stage of growth, while a growth stage by glyphosate interaction was observed with the glyphosate-resistant biotype. Plants in the large rosette stage were not as sensitive to glyphosate as the other two stages of growth. Horseweed seed buried at 1 or 10 cm of depth in the field did not respond the same way at two locations. However, in general, seed viability was greater over a 36 month period at the 10 cm depth than at the 1 cm depth. Seeding a rye (Secale cereale) cover crop in the fall reduced the size and density of horseweed plants when evaluate the following spring, but not to commercially acceptable levels. In addition, although the individual horseweed plants were smaller, their susceptibility to paraquat and 2,4-D was not different from larger horseweed plants grown without the rye competition. Research to date at the University of Delaware has shown little to no biological or ecological differences between glyphosate-resistant and glyphosate-susceptible horseweed biotypes. Future research needs to focus on management practices that reduce the selection pressure for development of multiple-resistant biotypes. Continued research on horseweed ecology and biology is critical to lessen this resistance pressure.

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DO ECOLOGICAL INSIGHTS INFORM CONYZA MANAGEMENT? D.A. Mortensen, J.T. Dauer, W.S. Curran, The Pennsylvania State Univ., University Park, and M.J. VanGessel, Univ. of Delaware, Georgetown. ABSTRACT Over the past four plus years we have conducted numerous life history, dispersal, and simulation studies and on-farm surveys to understand the nexus of glyphosate resistant horseweed (Conyza canadensis) population dynamics and management. During that time the spatial extent of this invasive genotype increased approximately five fold. This rapid invasion speed can be explained by long-distance propagule dispersal and high recruitment success. In fact, we have observed seeds reaching the atmospheric boundary layer. Aerial sampling has detected Conyza seed at altitudes in excess of 100 meters above the ground surface. The implications of such findings are profound, once aloft at such altitudes it is likely that seed could travel tens of kilometers in a single day. Given that seed are released over a period of some six weeks, there is ample opportunity for very long-distance seed movement. The practical implication of these findings is that fields and farmsteads are far more highly interconnected than previously thought. Effectively, a grower could inherit the downside consequences of poor management from a neighbor many kilometers away. Another implication of these findings is that buffer distances between "invaded" and “uninvaded” farmsteads must be sufficiently large to limit the possibility of resistant horseweed gaining a foothold in new farms or farming regions. Finally, real costs have been incurred by this resistance outbreak. In the region where the on-farm surveys are being conducted, the cost of weed control has increased significantly as the efficacy of glyphosate has decreased. It is clear that successful approaches at minimizing the spread of the plant will require an area-wide approach. It may also be the case that such an approach will be required once a local growing region has been invaded.

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THE MASSACHUSETTS EXAMPLE: ONE STREAM BANK, MULTIPLE JURISDICTIONS. R.G. Prostak and D.J. Picking, Univ. of Massachusetts, Amherst. ABSTRACT In MA, individuals wishing to control or eradicate invasive plants in riparian areas face many regulations that are unique to the commonwealth. These regulations predate invasive plant recognition and consciousness to the degree that it exists today. In 1972, the Commonwealth of MA passed the Wetlands Protection Act (WPA), MA General Laws Chapter 131 section 40. The Act defines areas subject to protection, including Bordering Vegetative Wetlands (BVW), stream banks, and lands subject to flooding. The Act protects not only BVW but identifies a 100 foot buffer zone beyond the wetland edge. The Act requires that a permit be obtained for nearly all activities within the BVW. Activities in the wetland buffer zone may or may not require a permit depending on the likelihood of the activity adversely impacting the resource area. In 1996, MA passed the Rivers Protection Act (RPA) that further amended the WPA. RPA establishes a 200 foot resource area along all perennial rivers and streams. This is a regulated resource area and may or may not overlap a BVW and its associated buffer zone. Almost all activities within this area will require a permit. The WPA is administered by a local Conservation Commission in each municipality with oversight and final authority from the MA Department of Environmental Protection (DEP). Under "home rule" in MA, municipalities may pass local wetland bylaws that are more stringent than those of the commonwealth. For example, some municipalities have imposed 'no build' and /or ‘no disturb’ zones adjacent to wetland resource areas that prohibit all activities within these locally defined zones. Decisions made based on the WPA by municipal conservation commissions may be appealed to the DEP, but decisions made based on local by-laws can not be appealed. Local conservation commissioners serve voluntarily once appointed by local town officials. Training programs are offered by the MA Association of Conservation Commissioners but attendance at these programs is not mandatory. The make-up of commissions varies significantly from town to town due to the professional background and experience of the commissioners, therefore, decisions and interpretations of regulation can also vary. The importance of invasive plant management is recognized by most (if not all) local conservation commissions, however, conservation commission differ widely in their views on the use of herbicides in or near wetlands. Another set of regulations that may impact ones ability to manage invasive plants in riparian zones is the MA Endangered Species Act, MA General Law Chapter 131 A. The Act is administered by Natural Heritage Endangered Species Program (NHESP) within the MA Department of Fish and Game and reviews all proposed activities in estimated rare or endangered species habitat, as delineated on the NHESP database. With the exception of utility right-of-ways, the WPA and RPA do not address the use of herbicides. The exclusive authority for the regulation of the labeling, distribution, sale, storage, transportation, use and application, and disposal of pesticides in the commonwealth is determined by the MA Pesticide Control Act, MA General Law Chapter 132B administered by the MA Department of Agricultural Resources.

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Supplement to the Proceedings Sixtieth Annual Meeting of the Northeastern Weed Science Society Westin Hotel Providence, RI January 3-6, 2006

Hilary A. Sandler, Editor University of Massachusetts-Amherst Cranberry Station East Wareham, MA

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Supplemental NEWSS Abstracts (presented in alphabetical order, by author) THE EFFECTS OF CULTURAL PRACTICES ON WEED ESTABLISHMENT IN CONTAINERS. J. Altland, Oregon State University, Corvallis. ABSTRACT Cultural management practices in nurseries influence weed establishment and growth in containers. The three cultural practices that have the most impact on container weed management are substrate particle size selection, fertilizer management, and irrigation management. Seeds of most container weeds are small. Small seeds must germinate on or near the substrate surface because they do not have sufficient stored energy to survive deep germination. Water within in a container is not constant from the surface to the bottom. Due to matric potential of substrates, there is a gradient of available water from high to low in the container bottom up to the surface. Coarse substrates do not have sufficient water holding capacity to support seed germination, particularly on the substrate surface where weed seeds germinate. For example, within the range of bark grades used by nurseries, coarser grades reduce pearlwort (Sagina procumbens) growth compared to finer grades. Water holding capacity is an important physical property of container substrates, and also dictates the amount of water available to the ornamental crop. Moderation in selecting coarse substrates is important. Fertilizers can be used to impact weed growth. Bark substrates, including those amended with peat, pumice, sand, or choir, have little or no available nitrogen (N). N is required by weeds for successful germination and growth. Placement of controlled release fertilizers (CRFs) below the substrate surface, commonly called dibbling, results in no available N on the substrate surface and thus poor weed establishment. Topdressing CRFs or injecting fertilizer through the irrigation system supplies abundant N to the substrate surface and improves weed establishment. Incorporating composts with high levels of available N into the substrate will also favor weed growth. If nursery conditions dictate that fertilizers must be injected through the irrigation system, N form can also influence weed growth. N in water soluble fertilizers is supplied in the form of nitrate, ammonium, urea, or in combination. Fertilizers that supply N solely in the form of nitrate, as opposed to either urea or ammonium plus nitrate, reduce weed growth and flowering. Differences in weed growth due to N form are subtle; however, reduced flower and seed numbers can result in significantly reduced weed pressure. Irrigation is the most difficult cultural practice to manage. Over-watering reduces herbicide effectiveness and improves weed establishment and growth. Irrigation monitoring can be used to better manage irrigation rates, especially with micro-irrigated crops. However, overhead irrigation systems lack uniformity. Non-uniform irrigation with overhead sprinklers is the greatest limitation to strict management of irrigation rates. Strict management of cultural practices alone will not eliminate weeds; however, it will reduce weed vigor and improve overall weed control. The most effective weed management program for nursery containers integrates sanitation, management of cultural practices, and proper use of preemergence herbicides. 120

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AMINOPYRALID: A NEW HERBICIDE FOR BROADLEAF WEED CONTROL IN PASTURE, ROADSIDE, AND NATURAL AREAS. P.L. Burch, Dow AgroSciences, Christiansburg, VA and E.S. Hagood, VPI and SU, Blacksburg. ABSTRACT Aminopyralid is a new systemic herbicide developed by Dow AgroSciences specifically for use on rangeland, pasture, rights-of-way, such as roadsides for vegetation management, Conservation Reserve Program acres, non-cropland, and natural areas in the United States and Canada. The herbicide is formulated as a liquid containing, 240 g ae/liter of aminopyralid as a salt. The herbicide has postemergence activity on established broadleaf plants and provides residual control of germinating seeds of susceptible plants. Field research has shown aminopyralid to be effective at rates between 52.5 and 120 g ae/ha, which is about 1/4 to 1/20 less than use rates of currently registered rangeland and pasture herbicides with the same mode of action including, clopyralid, 2,4-D, dicamba, picloram, and triclopyr. Aminopyralid controls over 40 species of annual, biennial, and perennial broadleaf weeds including Acroptilon repens, Artemisia absinthium, Carduus acanthoides, Carduus nutans, Centaurea diffusa, Centaurea maculosa, Centaurea solstitialis, Chrysanthemum leucantheum, Cirsium arvense, Cirsium vulgare, Lamium amplexicaule, Matricaria inodora, Ranunculus bulbosus, Rumex crispus, Solanum carolinense, Solanum viarum, and Xanthium strumarium. Most warm- and cool-season rangeland and pasture grasses are tolerant of aminopyralid applications at proposed rates. Research continues to determine the efficacy of aminopyralid on other key invasive weeds and on the role of aminopyralid in facilitating plant community improvement in land management programs.

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ABSTRACTS AND BIOGRAPHIES FOR PRESENTATIONS AT THE 7TH ANNUAL CONFERENCE OF THE NORTHEAST AQUATIC PLANT MANAGEMENT SOCIETY

4-5 JANUARY 2006 WESTIN PROVIDENCE PROVIDENCE, RHODE ISLAND

Abstracts and biographies are listed in order of presentation at the conference.

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EVALUATION OF REGISTERED AND EUP HERBICIDES FOR CONTROL OF VARIABLE MILFOIL. M.D. Netherland, U.S. Army Engineer Research and Development Center, Univ. of Florida Center for Aquatic and Invasive Plants, Gainesville. ABSTRACT Variable milfoil (Myriophyllum heterophyllum Michx.) is considered invasive in the Northeast US, and resource managers have expressed an interest in determining the aquatic herbicides that are most effective in controlling both pioneer and established infestations of the plant. We have initiated laboratory and mesocosm evaluations of 7 registered active ingredients (carfentrazone, copper, diquat, endothall, fluridone, triclopyr, and 2,4-D), and two acetolactate synthase (ALS) inhibitors that have recently received Experimental Use Permits in aquatics (imazamox and penoxsulam). Contact herbicide evaluations have focused on developing concentration and exposure time (CET) relationships, evaluations of 2,4-D and triclopyr have focused on CET relationships, response to formulation, and minimum rates required to achieve plant control. Fluridone and the ALS inhibitors have been evaluated to determine the minimum concentrations necessary to inhibit growth and pigment production. Preliminary results suggest that low doses (100 to 400 ppb) and extended exposures (7 to 21 days) of 2,4-D and triclopyr can be highly effective for control of variable milfoil. These treatments proved more effective than high dose (2 to 3 ppm) and shorter-term exposures (6 to 18 hours). Variable milfoil also tends to be quite susceptible to fluridone and the ALS inhibitors at rates in the range of 8 to 20 ppb. As with other nuisance plants, extended exposures of 60 to 100+ days to these concentrations will be necessary to provide control. In addition, studies suggest the phenology of variable milfoil will require that these treatments be applied early in the season prior to or just as the plants start to come out of winter dormancy. Contact herbicide evaluations are ongoing and will be reported at the meeting. ---------Mike Netherland is a Research Biologist for the US Army Engineer Research and Development Center. He is located at the University of Florida Center for Aquatic and Invasive Plants and is a courtesy Associate Professor in the Department of Agronomy. Dr. Netherland received an M.S. in Botany and Plant Pathology from Purdue University and his Ph.D. in Agronomy from the University of Florida. His dissertation topic evaluated the response of hydrilla tubers to various forms of management. From 1998 to 2003 Mike was employed by the SePRO Corporation as the Research Director for Aquatics. Both public and private sector research has focused on the response of exotic and native submersed plants to experimental and EPA registered herbicides. Dr. Netherland has worked with Myriophyllum spp. since 1988, and has conducted extensive research at the laboratory, mesocosm, and field-scale evaluating various control methods.

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EVALUATION OF AN HERBICIDE APPLICATION ON VEGETATED HABITAT AND THE STRUCTURE OF A FISH AND MACROINVERTEBRATE COMMUNITY IN MINNESOTA LAKES. J.G. Slade and E.D. Dibble, Department of Wildlife and Fisheries, Mississippi State Univ. ABSTRACT Macrophytes provide important habitat complexity mediating structure of aquatic communities in lakes. We investigate the hypothesis that removal of exotic, invasive macrophytes because of changes in this complexity will alter fish and macroinvertebrate populations. A four lake experiment was conducted in the Minneapolis, Minnesota metropolitan area (June 2003-September 2004) to measure herbicide effects on the structure of the aquatic community. A BACI (before–after/control–impact) sampling design was used to evaluate change in structural habitat (stem frequency) by removing two exotic plant species (Myriophyllum spicatum and Potamogeton crispus) and its effect on the abundance and richness of fish and macroinvertebrates. As an experimental treatment, a low-dose, species-specific herbicide application was made to remove the two species in two of the lakes. Pre- and post-treatment fish and macroinvertebrate population data were collected, and the treatment effect was evaluated using repeated measures two-way analysis of variance. A multi-sampling approach using popnets, boat-mounted electrofishing, and seining was deployed to ensure accuracy in fish data. Our data documented significant loss of the two exotic species however no treatment effect was noted on macrophyte stem frequency, or abundance and richness of the fish and macroinvertebrate community. No change in stem frequency was noted due to the immediate replacement by native macrophytes. Temporal (seasonal) effect in the abundance and richness of macrophyte, fish, and macroinvertebrate communities was noted. We conclude that there was no immediate effect of removing the habitat complexity on the fish and macroinvertebrate community by using an herbicide to remove two exotic macrophytes in the four Minnesota Lakes. ----------

Jeremy Slade is a recent graduate from the Department of Wildlife and Fisheries, Mississippi State University (MSU). Completed degree August 2005: Master's of Wildlife and Fisheries Science. Performed Master's work on fish-plant relationships pre- and post- herbicide application in four Minnesota lakes. Currently employed by the Department of Wildlife and Fisheries, MSU as a Research Associate and contracted (work) for United States Army Corps of Engineers, US Army Research and Development Center (ERDC), Vicksburg, MS. Married June 4, 2005 in Quito, Ecuador to wife Cristina.

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USE OF THE AQUATIC HERBICIDE RENOVATE™ (TRICLOPYR) IN PHRAGMITES AUSTRALIS CONTROL PROGRAMS. D. Roach, All Habitat Services, LLC, S. Hyde, SePRO Corporation, and S. Living, All Habitat Services, LLC. ABSTRACT SePRO Corporation, in cooperation with All Habitat Services, LLC, has conducted experimental trials to evaluate the effectiveness of the aquatic herbicide Renovate (triclopyr TEA) to control the invasive species Phragmites australis. Renovate is a proven systemic aquatic herbicide used for selective control of broadleaf (dicots) and woody plants. Field development work from 2003-2005 has demonstrated a significant ability to control invasive Phragmites (monocot) populations. The effectiveness of Renovate early in the growing season and the opportunity of rapid recovery of desirable grass (monocot) species provide a new and valuable tool in the management of Phragmites australis. Important benefits include; an expanded management window, release of desirable monocot species, reduced biomass, compressed restoration timelines, and perennial rhizome suppression. The presentation will include a discussion of current Phragmites control programs, pre-treatment and post-treatment observations from Renovate field evaluation projects, as well as information on the future potential of Renovate prescriptions in Phragmites management programs. ™ Trademark of Dow AgroSciences LLC, manufactured for SePRO Corporation. ----------

David Roach is the General Manager of All Habitat Services, LLC, an innovator in the field of wetland and upland habitat management. He holds commercial supervisory pesticide applicator licenses for categories of Aquatic Pest, Right of Way, Bird, Mosquitoes and Biting Flies, and Public Health in Connecticut and Aquatic Pest and Public Health in New York. David works collaboratively with manufacturers and government scientists to develop highly effective, wise use prescriptions. He has 10 years experience in both vegetation management and public health mosquito management programs.

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ALUMINUM TREATMENT FOR PHOSPHORUS AND ALGAE CONTROL: WHAT, WHY, WHERE AND WHEN. K.J. Wagner, ENSR, International. ABSTRACT The use of aluminum compounds as coagulants has long been practiced in the water and wastewater industries, so use of aluminum is neither novel nor new. Their use to bind up phosphorus in lakes dates back about 35 years, with many more treatments in the last decade or two and considerable lessons learned. Multiple factors must be evaluated when developing an aluminum dosing program, including the target location of phosphorus (incoming water, standing lake water, sediment reserves), the amount of phosphorus to be inactivated, existing water chemistry (especially pH and alkalinity), and potentially sensitive receptor populations in the aquatic environment. In general, the aluminum dose to effectively inactivate phosphorus in the target location will be 10 to 100 times the available phosphorus concentration, with several methods used to determine available phosphorus. Longevity of results depends upon the length of time it takes for inactivated phosphorus to be replaced. Where internal recycling is the primary source of phosphorus, reduced levels are expected for more than a decade and have lasted for over 20 years in real cases. Where external inputs are dominant, improvement can be expected for 3 to 5 times the detention time of the system, which may be as short as a season. While aluminum can be toxic to aquatic fauna in its reactive form, reactions occur quickly and result in non-toxic forms that bind phosphorus and some other contaminants in a largely permanent manner. Approaches for minimizing toxicity include keeping the pH between 6.0 and 8.0 SU, with a strong preference for pH levels between 6.5 to 7.5 SU, keeping the applied aluminum level